Document:

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                                                                    Exhibit 10.4

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                            STOCK PURCHASE AGREEMENT

                                     Among

                        CarrAmerica Realty Corporation,
          OmniOffices (UK) Limited (solely for purposes of Article II,
                           Article IV and Article V)
                                      and
OmniOffices (Lux) 1929 Holding Company S.A. (solely for purposes of Article II,
                          Article IV and Article V),
                                on the one hand

                                      and

                             VANTAS Incorporated,

                       Reckson Services Industries, Inc.
           (solely for purposes of Section 5.4, 6.2 and Article XXI)
                               on the other hand

                         Dated as of January 20, 2000

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                               Table of Contents

                                                                          PAGE
                                   ARTICLE I
                               The Transactions

Section 1.1 The Transactions...................................................2
Section 1.2 The Closing........................................................2

                                  ARTICLE II
       Representations and Warranties of CarrAmerica, OMNI UK and LuxCo

Section 2.1 Organization and Standing; Books and Records.......................2
Section 2.2 Authority..........................................................3
Section 2.3 No Conflicts; Consents.............................................3
Section 2.4 Capital Stock of the Companies.....................................4
Section 2.5 Equity Interests...................................................5
Section 2.6 Investment Companies...............................................5
Section 2.7 Restrictions and Agreements........................................5
Section 2.8 Financial Statements; Undisclosed Liabilities......................5
Section 2.9 Absence of Changes or Events.......................................6
Section 2.10 Taxes.............................................................7
Section 2.11 Assets Other than Real Property Interests.........................8
Section 2.12 Real Property.....................................................8
Section 2.13 Contracts........................................................11
Section 2.14 Litigation.......................................................13
Section 2.15 Insurance........................................................13
Section 2.16 Benefit Plans....................................................13
Section 2.17 Compliance with Applicable Laws..................................15
Section 2.18 Labor Matters....................................................15
Section 2.19 Transactions with Affiliates.....................................16
Section 2.20 Corporate Name...................................................16
Section 2.21 Customers........................................................16
Section 2.22 Intellectual Property............................................16
Section 2.24 Brokers..........................................................19
Section 2.25 Competition......................................................19
Section 2.26 Data Protection..................................................19
Section 2.27 Equivalence......................................................19

                                  ARTICLE III
                   Representations and Warranties of VANTAS

Section 3.1 Organization and Standing.........................................20
Section 3.2 Authority.........................................................21
Section 3.3 No Conflicts; Consents............................................21

                                  ARTICLE IV
                        Agreements of OMNI UK and LuxCo

Section 4.1...................................................................21

                                   ARTICLE V
                               Mutual Covenants

Section 5.1 Consummation of the Transactions..................................25
Section 5.2 Publicity.........................................................25

                                  ARTICLE VI
                             Conditions to Closing

Section 6.1 Each Party's Obligation...........................................26
Section 6.2 CarrAmerica's Obligation..........................................26
Section 6.3 VANTAS' Obligation................................................26
Section 6.4 Frustration of Closing Conditions.................................27

                                  ARTICLE VII
Further Assurances............................................................27

                                 ARTICLE VIII
Assignment....................................................................27

                                  ARTICLE IX
Third-Party Beneficiaries.....................................................28

                                   ARTICLE X
Termination...................................................................28

                                  ARTICLE XI
                             Intentionally Omitted

                                  ARTICLE XII
Amendments....................................................................29

                                 ARTICLE XIII
Notices.......................................................................29

                                  ARTICLE XIV
Interpretation; Exhibits and Schedules........................................31

                                  ARTICLE XV
Counterparts..................................................................31

                                  ARTICLE XVI
Litigation Costs..............................................................31

                                 ARTICLE XVII
Entire Agreement..............................................................32

                                 ARTICLE XVIII
                             Intentionally Omitted

                                  ARTICLE XIX
Severability..................................................................32

                                  ARTICLE XX
Consent to Jurisdiction.......................................................32

                                  ARTICLE XXI
Governing Law.................................................................33

                                 ARTICLE XXII
Disclosure Schedules..........................................................33

                                 ARTICLE XXIII
Exclusive Remedy..............................................................33

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                            SCHEDULES AND EXHIBITS

Exhibit A           Shares
Exhibit B           Notes

Schedule 2.1        Organization and Standing; Books and Records
Schedule 2.4        Capital Stock of the Companies
Schedule 2.5        Equity Interests
Schedule 2.7        Restrictions and Agreements
Schedule 2.8        Financial Statements; Undisclosed Liabilities
Schedule 2.9        Absence of Changes or Events
Schedule 2.11       Assets Other than Real Property Interests
Schedule 2.12       Real Property
Schedule 2.13       Contracts
Schedule 2.14       Litigation
Schedule 2.15       Insurance
Schedule 2.16       Benefit Plans
Schedule 2.17       Compliance with Applicable Laws
Schedule 2.18       Labor Matters
Schedule 2.19       Transactions with Affiliates
Schedule 2.21       Customers
Schedule 2.22       Intellectual Property
Schedule 2.23       Environmental Liability

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                            INDEX TO DEFINED TERMS

Term                                                                 Page Number
----                                                                 -----------
Affiliate                                                                16
Agreement                                                                1
Applicable Laws                                                          14
Assumption Agreement                                                     26
Balance Sheets                                                           6
Benefit Plans                                                            14
Bona Fide Purchaser                                                      4
Buyer                                                                    1
Cap Ex Budgets                                                           22
CarrAmerica                                                              1
Closing                                                                  2
Closing Date                                                             2
Companies                                                                1
Consideration
Contracts                                                                13
Control                                                                  16
Controlled                                                               16
Controlling                                                              16
Customers                                                                16
Environment                                                              17
Financial Statements                                                     6
Financing Materials                                                      21
Governmental Entity                                                      4
Hazardous Substance                                                      17
HQ                                                                       1
HQ Merger                                                                1
Inland Revenue                                                           7
Intellectual Property                                                    16
Investment Company Act                                                   5
Lambert Smith Hampton                                                    16
Lambert Smith Hampton Group Limited                                      16
Loan Consideration                                                       2
Loan Notes                                                               26
Loans                                                                    1
LuxCo                                                                    1
LuxCo Owned Properties                                                   9
LuxCo Property(ies)                                                      9
LuxCo Real Property Lease                                                9
Lux Non-Voting Common Stock                                              1
MAM Investment                                                           19
Material Adverse Effect                                                  3
Merger Agreement                                                         1
Notes                                                                    1
Offices in the City of Vienna                                            16
Omni Offices                                                             16
Omni Offices (LUX) 1929 Holding Company S.A.                             16
OmniUK                                                                   1
OmniUK Property(ies)                                                     9
OmniUK Real Property Lease                                               9
Permit                                                                   17
Permitted Liens                                                          8
Phantom                                                                  3
Pre-Closing Tax Period                                                   7
Relevant Law                                                             17
RSI                                                                      1
Seller                                                                   1
Share Consideration                                                      1
Shares                                                                   1
Summary                                                                  25
Stock Purchase Agreement                                                 1
Subsidiary                                                               3
Tax                                                                      7
Taxes                                                                    7
Tax Return                                                               7
Total Consideration                                                      2
UK Non-Voting Common Stock                                               1
VANTAS                                                                   1
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     STOCK PURCHASE AGREEMENT (this "Agreement"), dated as of January 20, 2000
between CarrAmerica Realty Corporation, a Maryland corporation ("CarrAmerica"
or "Seller"), OmniOffices (UK) Limited, a corporation formed under the laws of
England ("Omni UK") (solely for purposes of Article II, Article IV and Article
V) and OmniOffices (Lux) 1929 Holding Company S.A., a corporation formed under
the laws of Luxembourg, ("LuxCo" and together with Omni UK, collectively, the
"Companies") (solely for purposes of Article II, Article IV and Article V) on
the one hand, and VANTAS Incorporated, a Nevada corporation ("Buyer" or
"VANTAS"), and Reckson Services Industries, Inc., a Delaware corporation
("RSI") (solely for purposes of Section 5.4, 6.2 and Article XXI), on the
other hand.

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                             W I T N E S S E T H:

     WHEREAS, CarrAmerica own shares of the capital stock of each of (i) OMNI
UK and (ii) LuxCo;

     WHEREAS, CarrAmerica has made certain loans to OMNI UK and LuxCo as
described on Exhibit B attached hereto (the "Loans") which Loans are evidenced
by promissory notes, the dates and denominations of which are set forth on
Exhibit B (the "Notes");

     WHEREAS, CarrAmerica desires to sell and transfer to VANTAS and VANTAS
desires to purchase from CarrAmerica (i) 2,006,066 shares of non-voting common
stock, par value (pound).01 per share, of OMNI UK (which represents
approximately 95% of the equity interest in Omni UK) (the "UK Non-Voting
Common Stock") and 144 shares of non-voting common stock, par value $250 per
share, of LuxCo (which represents approximately 95% of the equity interest in
LuxCo) (the "Lux Non-Voting Common Stock"; and together with the UK Non-Voting
Common Stock, collectively, the "Shares") owned of record by the Seller for
$23,972,306 in cash payable in accordance with Section 1.2 (such amount based
on assumed Loan Consideration of $44,995,277 and subject to recalculatation at
Closing pursuant to Annex A, the "Share Consideration") and (ii) the Notes in
exchange for an amount equal to the principal amount of, and any accrued and
unpaid interest with respect to, the Notes as of the Closing Date in
accordance with Section 1.2 (the "Loan Consideration");

     WHEREAS, CarrAmerica desires to assume certain obligations of Omni UK
upon the terms set forth in Section 5.3;

     WHEREAS, simultaneously with the execution and delivery of this
Agreement, (i) Buyer, Seller, RSI and HQ Global Workplaces, Inc. ("HQ") have
entered into an Agreement and Plan of Merger (the "Merger Agreement") that
provides for the merger, subject to and upon the terms and conditions set
forth therein, of VANTAS with and into HQ (the "HQ Merger") immediately prior
to the closing of the transactions contemplated hereby and (ii) Seller and RSI
have entered into that certain Stock Purchase Agreement (the "Stock Purchase
Agreement") providing for the acquisition by RSI from Seller of certain shares
of voting common stock and non-voting common stock of HQ simultaneously with
the closing of the transactions contemplated hereby;

     WHEREAS, capitalized terms not defined herein have the meanings ascribed
to them in the Merger Agreement; and

     NOW, THEREFORE, in consideration of the mutual covenants and undertakings
contained herein, and subject to and on the terms and conditions herein set
forth, the parties hereto agree as follows:

                                   ARTICLE I

                               The Transactions

     Section 1.1 The Transactions. (a) Upon the terms and subject to the
conditions contained herein, on the Closing Date (as hereinafter defined),
CarrAmerica will sell, convey, transfer, assign and deliver to VANTAS, and
VANTAS will purchase and acquire from CarrAmerica, the number of Shares set
forth opposite its name on Exhibit A attached hereto for the Share
Consideration, payable as set forth below in Section 1.2.

     (b) Upon the terms and subject to the conditions contained herein, on the
Closing Date, CarrAmerica will sell, convey, transfer, assign and deliver to
VANTAS, and VANTAS will purchase and acquire from CarrAmerica, the Notes for
the Loan Consideration, payable as set forth below in Section 1.2.

     Section 1.2 The Closing. The Closing (the "Closing") of the purchase and
sale of the Shares shall be held at the offices of Brown & Wood LLP, One World
Trade Center, New York, New York 10048, immediately after the Effective Time
of the HQ Merger and immediately prior to the Effective Time of the Second
Step Merger, subject to the satisfaction or waiver of the conditions set forth
in Article VII herein. The date on which the Closing shall occur is
hereinafter referred to as the "Closing Date." At the Closing, (i) VANTAS
shall deliver to CarrAmerica, by wire transfer to a bank account designated in
writing by CarrAmerica at least two business days prior to the Closing Date,
immediately available funds in an amount equal to the sum of (A) the Loan
Consideration and (B) the Share Consideration (such sum of (A) and (B) being
referred to herein as, collectively, the "Total Consideration") and (ii)
CarrAmerica shall deliver or cause to be delivered to VANTAS (a) certificates
representing the Shares, duly endorsed in blank or accompanied by stock powers
duly endorsed in blank in proper form for transfer, with appropriate transfer
stamps, if any, affixed and (b) the originally executed Notes, duly endorsed
by the Seller, without recourse, for transfer to VANTAS.

                                  ARTICLE II

       Representations and Warranties of CarrAmerica, OMNI UK and LuxCo

     (A) OMNI UK and LuxCo hereby severally with respect to itself and its

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Subsidiaries represent and warrant to VANTAS as follows:

     Section 2.1 Organization and Standing; Books and Records.

     (a) Each of the Companies is a corporation duly organized and validly
existing under the laws of its jurisdiction of incorporation. Schedule 2.1
sets forth each Subsidiary (as defined below) of each of the Companies and the
state or other jurisdiction of organization of such Subsidiary and the
percentage ownership of each of the Companies with respect to each such
Subsidiary. Each of the Companies and each of its respective Subsidiaries have
all requisite corporate power and authority necessary to carry on their
respective businesses as presently conducted and to enable each to own, lease
or otherwise hold their respective properties and assets. Each of the
Companies and their respective Subsidiaries are duly qualified to do business
as a foreign corporation in each jurisdiction in which the conduct or nature
of their respective business or the ownership, leasing or holding of their
respective properties or assets makes such qualification necessary, except
such jurisdictions where the failure to be so individually or in the
aggregate, would not have a material adverse effect on the business, financial
condition or results of operations of either of the Companies and their
respective Subsidiaries, taken as a whole (a "Material Adverse Effect"). The
term "Subsidiary", for any Person, means each person of which a majority of
the voting power of the voting equity securities or equity interest is owned,
directly or indirectly, by such Person.

     (b) Each of the Companies has made available to VANTAS true and complete
copies of its respective certificate of incorporation and by-laws (or
equivalent organizational document), each as amended to date. The stock
certificate and transfer books and the minute books of the Companies (which
have been made available for inspection by VANTAS prior to the execution and
delivery of this Agreement) are true and complete.

     Section 2.2 Authority. Each of the Companies has all requisite corporate
power and authority to enter into this Agreement, to perform its obligations
hereunder and to consummate the transactions contemplated hereby. All acts and
other proceedings required to be taken by the Companies to authorize the
execution, delivery and performance of this Agreement and the consummation of
the transactions contemplated hereby have been duly and properly taken. This
Agreement has been duly executed and delivered by a duly authorized officer of
each of the Companies and constitutes a legal, valid and binding obligation of
each of the Companies, enforceable against each of the Companies in accordance
with its terms except insofar as enforcement thereof may be limited by
bankruptcy, insolvency or other laws relating to or affecting enforcement of
creditors' rights generally including such general equity principles as may
apply in the enforcement of creditors' rights.

     Section 2.3 No Conflicts; Consents. Except as set forth on Schedule 2.3,
the execution and delivery of this Agreement by each of the Companies does
not, and the consummation of the transactions contemplated hereby and
compliance by the Companies with the terms hereof will not, conflict with, or
result in any violation of or default (with or without notice or lapse of
time, or both) under, or give rise to a right of termination, cancellation or
acceleration of any obligation or to material loss of a benefit under, or
result in the creation of any lien, charge or encumbrance of any kind upon any
of the properties or assets of either of the Companies under, any provision of
(i) the certificate of incorporation or by-laws (or equivalent organizational
document) of either of the Companies, (ii) any material note, bond, mortgage,
indenture, deed of trust, loan document, license, lease, contract, commitment,
agreement or arrangement to which either of the Companies is a party or by
either of the Companies or any of their respective properties or assets is
bound or (iii) any judgment, order or decree, or statute, law, ordinance, rule
or regulation, applicable either of the Companies or any of their respective
properties or assets. Except as set forth on Schedule 2.3, no consent,
approval, license, permit, order or authorization of, or registration,
declaration or filing with, any Federal, state, local or foreign government or
any court of competent jurisdiction, administrative agency or commission or
other governmental authority or instrumentality, domestic or foreign, or any
national securities or commodities exchange or other regulatory or
self-regulatory body or association (a "Governmental Entity") is required to
be obtained or made by or with respect to either of the Companies in
connection with the execution, delivery and performance of this Agreement by
the Companies or the consummation of the transactions contemplated hereby,
other than compliance with any filings under the HSR Act.

     Section 2.4 Capital Stock of the Companies.

     (a) As of the date hereof, the authorized share capital of (i) OMNI UK
consists of 200,000 shares of UK Voting Common Stock and 3,800,000 shares of
UK Non-Voting Common Stock, one share of Class C Redeemable Preference Share,
(pound).01 per share par value, and one share of Class D Redeemable Preference
Share, (pound).01 per share par value ("Class D Stock") of which 105,582
shares of UK Voting Common Stock, 2,006,066 shares of UK Non-Voting Common
Stock, one share of Class C Stock and one share of Class D Stock are duly
authorized and validly issued and outstanding, fully paid and nonassessable
and (ii) LuxCo consist of 1000 shares of LUX Voting Common Stock and 1000
shares of Lux Non-Voting Common Stock, of which 144 shares of Lux Voting
Common Stock and 144 shares of Lux Non-Voting Common Stock are duly authorized
and validly issued and outstanding, fully paid and non-assessable. Except as
set forth on Schedule 2.4, no such shares have been issued in violation of, or
are subject to, any purchase option, call, right of first refusal, preemptive,
subscription or similar right under any provision of applicable law, the
certificate of incorporation or by-laws (or equivalent organizational
<PAGE>

document) of either of the Companies or any agreement, contract or instrument
to which either of the Companies is a party or by which either or any of their
respective properties or assets is bound. Except as set forth on Schedule 2.4
and except for the Notes made by LuxCo which are convertible at the holder's
option into Lux Non-Voting Common Stock, there are no outstanding warrants,
options, rights, "phantom" stock rights, agreements, convertible or
exchangeable securities or other commitments (other than this Agreement) (i)
pursuant to which either of the Companies is or may become obligated to issue,
sell, purchase, return or redeem any shares of capital stock or other
securities of either of the Companies or (ii) that give any person the right
to receive any benefits or rights similar to any rights enjoyed by or accruing
to the holders of shares of capital stock of either of the Companies. There
are no equity securities of either of the Companies reserved for issuance for
any purpose except for securities reserved for issuance for the purposes set
forth on Schedule 2.4. There are no outstanding bonds, debentures, notes or
other indebtedness having the right to vote on any matters on which
shareholders of either Company may vote.

     (b) Ownership of Capital Stock of the Companies; the Shares. CarrAmerica
is the record and beneficial owner of the number of Shares set forth opposite
it's name on Exhibit A hereto. CarrAmerica has good and valid title to the
Shares and the Notes, in each case free and clear of any liens, charges,
claims, rights or encumbrances of any kind. Other than the Shares owned by HQ
and as otherwise set forth on Schedule 2.4(b) and except for 1 Class C Share
(par value $.01) of Omni UK and 1 Class D Share (par value $.01) of Omni UK,
the Shares represent all of the issued and outstanding shares of capital stock
of each of the Companies.

     (c) Assuming VANTAS is a "bona fide purchaser" within the meaning of the
Uniform Commercial Code of the State of New York, upon delivery to VANTAS at
the Closing of certificates representing the Shares and the Notes, in each
case duly endorsed by the Seller for transfer to VANTAS, and upon the Seller's
receipt of the Total Consideration, good and valid title to the Shares and
Notes will pass to VANTAS, free and clear of any liens, charges, claims,
rights or encumbrances of any kind. Except as set forth in Schedule 2.17 with
respect to Brook Street or in Schedule 2.4(c), other than this Agreement, none
of the Shares or Notes are subject to any agreement, contract, commitment,
understanding or arrangement, including any such agreement, contract,
commitment, understanding or arrangement restricting or otherwise relating to
the voting, dividend rights or disposition of the Shares or, in the case of
the Notes, subordinating the payment obligations under the Notes to any other
indebtedness or otherwise limiting any of the Seller's rights to enforce the
Notes.

     Section 2.5 Equity Interests. Except as set forth in Schedule 2.5 and the
other Schedules hereto, neither of the Companies nor any of their respective
Subsidiaries directly or indirectly owns any capital stock of or other equity
interests in any corporation, partnership or other person, and neither of the
Companies are members of or participants in any partnership, joint venture or
similar person.

     Section 2.6 Investment Companies. Neither of the Companies nor any of
their respective Subsidiaries is registered or required to be registered as an
Investment Company under the Investment Company Act of 1940, as amended (the
"Investment Company Act").

     Section 2.7 Restrictions and Agreements. Except as set forth in Schedule
2.7, (i) neither of the Companies nor any of their respective Subsidiaries is
a party to, nor are the Companies or any of their respective Subsidiaries or
any of their respective properties or assets subject to or bound by, any
judgment, order or decree of any Governmental Entity which has or is
reasonably likely to have, individually or in the aggregate, a Material
Adverse Effect, and (ii) neither of the Companies nor any of their respective
Subsidiaries is a party to, nor are any of their respective properties or
assets subject to or bound by, any contract, agreement or other instrument,
which, as a result of the execution of this Agreement or the consummation of
the transactions contemplated hereby, has or is reasonably likely to have,
individually or in the aggregate, a Material Adverse Effect.

     Section 2.8 Financial Statements; Undisclosed Liabilities.

     (a) Schedule 2.8 sets forth (A) the unaudited consolidated balance sheets
of each of the Companies as of September 30, 1999 (collectively, the "Balance
Sheets"), and the unaudited consolidated statements of income of each of the
Companies for the 9 month period ended September 30, 1999, and (B) the audited
consolidated balance sheets of Omni UK as of December 31, 1998, and the
audited consolidated statements of income of Omni UK for the period April to
December 31, 1998, (for Omni UK, the financial statements described in clauses
(A) and (B) above, together with the notes to such financial statements, are
collectively referred to herein as the "Financial Statements"). The Financial
Statements are in all material respects in accordance with the respective
books and records of the Companies and have been prepared in conformity with
generally accepted accounting principles applying in the country or state of
incorporation consistently applied throughout the periods indicated (except in
each case as described in the notes thereto) and on that basis fairly present
in all material respects (subject, in the case of the unaudited statements
referred to in (A) above, to normal, recurring year-end adjustments) the
financial condition and results of operations of Omni UK and its Subsidiaries
as of the respective dates thereof and for the respective periods indicated.

     (b) Neither of the Companies nor any of their respective Subsidiaries
have any liabilities or obligations of any nature (whether accrued, absolute,
<PAGE>

contingent, threatened or otherwise), except (A) as disclosed, reflected or
reserved against in the respective Balance Sheets and the notes thereto, (B)
items set forth on Schedule 2.8, (C) liabilities and obligations incurred in
the ordinary course of business consistent with past practice since the date
of the respective Balance Sheets that would not, individually or in the
aggregate, result in a Material Adverse Effect and (D) Taxes.

     (c) Except as set forth in Schedule 2.8, the amount of all accounts
receivable, including unbilled invoices which are reflected as accounts
receivable on the respective Financial Statements, due, or recorded in the
respective Balance Sheets as being due to the respective Companies and their
respective Subsidiaries (less the amount of any provision or reserve therefor
made in the respective Balance Sheets), are fully collectible in the normal
course of business.

     Section 2.9 Absence of Changes or Events. Since the date of the
respective Balance Sheets, there has not been any Material Adverse Effect or
any development or change in circumstances that is reasonably likely to result
in a Material Adverse Effect. Except as set forth in Schedule 2.9 or as
otherwise contemplated or permitted by this Agreement, since the date of the
respective Balance Sheets, the business of each of the Companies and their
respective Subsidiaries has been conducted in the ordinary course and in
substantially the same manner as previously conducted, and neither of the
Companies nor any of their respective Subsidiaries has (i) declared or paid
any dividend or made any other distribution to its respective shareholders
whether or not upon or in respect of any shares of their respective capital
stock, (ii) redeemed or otherwise acquired any shares of their respective
capital stock or issued any capital stock or any option, warrant or right
relating thereto or any securities convertible into or exchangeable for any
shares of their respective capital stock, (iii) adopted or materially amended
any Benefit Plan (as defined in Section 2.16), except as required by law, or
entered into or amended any employment, severance or consulting agreement,
contract or similar arrangement, (iv) granted to any their respective
directors, officers or employees any increase in compensation or benefits,
except for increases for any such director, officer or employee in the
ordinary course of business consistent with past practice or as may be
required under existing agreements, (v) incurred or assumed any liability,
obligation or indebtedness for borrowed money or guaranteed any such
liability, obligation or indebtedness, (vi) permitted, allowed or suffered any
of their respective assets to become subject to any mortgage, security
interest, lien or other similar restriction of any nature whatsoever, (vii)
cancelled any indebtedness or waived any claims or rights of substantial
value, except for customer trade adjustments in the ordinary course of
business that for either Company do not exceed $25,000 individually or
$100,000 in the aggregate, (viii) entered into, or modified, amended,
terminated, or permitted the lapse of, any real property lease or other
material agreement relating to real property, or (ix) incurred any
indebtedness that is senior to the Notes in terms of rights of payment.

     Section 2.10 Taxes.

     (a) For purposes of this Agreement, (A) "Tax" or "Taxes" shall mean all
taxes, and all other charges, fees, levies or other assessments of a fiscal
nature, including, without limitation, income, gross receipts, excise,
property, sales, withholding, social security, national insurance, franchise,
transfer and recording taxes, subscription taxes, fees and charges, including
estimated taxes, imposed by the United Kingdom or any taxing authority
(domestic or foreign), whether computed on a separate, consolidated, unitary,
combined or any other basis; and such term shall include any interest, fines,
penalties or additional amounts attributable to, or imposed upon, or with
respect to any such taxes, charges, fees, levies or other assessments; (B)
"Tax Return" shall mean any return, report or other document or information
required to be supplied to a taxing authority in connection with Taxes; (C)
"Inland Revenue" shall mean the U.K. Inland Revenue and (D) "Pre-Closing Tax
Period" shall mean all taxable periods ending on or before the Closing Date
and the portion ending on the Closing Date of any taxable period that includes
(but does not end on) such day.

     (b) In the last five years, the only jurisdictions where either of the
Companies and their respective Subsidiaries have filed any income or
subscription tax returns, as applicable, are the United Kingdom, Germany and
Luxembourg, and certain of the Companies' Subsidiaries have filed payroll
related (but not income) tax returns in Austria).

     (c) Except as set forth on Schedule 2.10, (A) Each of the Companies and
their respective Subsidiaries have (x) duly filed with the appropriate
Governmental Entities all Tax Returns required to be filed by them on or prior
to the date hereof (after giving effect to any filing extension properly
granted by a Governmental Entity having authority to do so), and such Tax
Returns are true, correct and complete in all material respects and (y) duly
paid in full or made provision in accordance with generally accepted
accounting principles for the payment of all Taxes for all periods ending
through the date hereof; (B) there are no liens for Taxes upon the assets of
any of the Companies and their respective Subsidiaries, except for statutory
liens for current Taxes not yet due; (C) each of the Companies and their
respective Subsidiaries have complied in all respects with all applicable
laws, rules and regulations relating to the payment and withholding of Taxes
and have, within the time and the manner prescribed by law, withheld from and
paid over to the proper Governmental Entities all amounts required to be so
withheld and paid over under applicable laws; (D) no audits or other
administrative proceedings or court proceedings are presently pending with
regard to any Taxes or Tax Returns of any of the Companies and their
<PAGE>

respective Subsidiaries and none of the Companies and their respective
Subsidiaries have received notice of any pending audits or proceedings; (E)
there are no outstanding written requests, agreements, consents or waivers to
extend the statutory period of limitations applicable to the assessment of any
Taxes or deficiencies against either of the Companies or their respective
Subsidiaries; (F) neither of the Companies nor their respective Subsidiaries
is a party to any agreement providing for the allocation or sharing of Taxes;
and (G) no power of attorney has been executed by either of the Companies or
their respective Subsidiaries with respect to any matter relating to Taxes
which is currently in force.

     Section 2.11 Assets Other than Real Property Interests.

     (a) Each of the Companies has good and valid title to all assets (other
than real property interests) reflected on their respective Balance Sheets or
acquired after the date thereof, except those sold or otherwise disposed of
since the date of their respective Balance Sheets in bona fide arm's length
transactions made in the ordinary course of business consistent with past
practice and not in violation of this Agreement in each case free and clear of
all liens, charges or encumbrances of any kind except those subject to the
rights of suppliers under retention of title clauses or similar provisions and
except (A) such as are set forth in Schedule 2.11, (B) mechanics', carriers',
workmen's, repairmen's or other like liens arising or incurred in the ordinary
course of business, liens arising under original purchase price conditional
sales contracts and equipment leases with third parties entered into in the
ordinary course of business and liens for Taxes that are not due and payable
or that may thereafter be paid without penalty and (C) other imperfections of
title or encumbrances, if any, that do not, individually or in the aggregate,
materially impair the continued use and operation of the assets to which they
relate in the businesses of the Companies and their respective Subsidiaries as
presently conducted (the liens and imperfections of title described in clauses
(B) and (C) above are hereinafter referred to collectively as "Permitted
Liens").

     (b) All of the Companies' respective material tangible personal property
has been maintained in accordance with the past practice of each such Company
and generally accepted industry practice. Each item of the Companies'
respective material tangible personal property is in reasonably good operating
condition and repair, ordinary wear and tear excepted. All of the Companies'
respective leased personal property is in all material respects in the
condition required of such property by the terms of the lease applicable
thereto during the term of the lease and upon the expiration thereof, and each
such Company has made all payments required by all such respective leases.

     Section 2.12 Real Property.

         (a) Neither of the Companies nor any of their respective Subsidiaries
owns any real property or interests in real property, other than OmniUK Real
Property Leases (as defined below) or LuxCo Real Property Leases (as defined
below), and the OmniUK Owned Property (as defined below), as applicable.
Schedule 2.12 sets forth a complete list of all real property and interests in
real property owned, leased or otherwise held by OmniUK and its Subsidiaries
(such leased properties, individually, an "OmniUK Real Property Lease," and
the real properties specified in such leases being referred to herein
individually as an "OmniUK Property" and collectively as the "OmniUK
Properties," and the owned property, the "OmniUK Owned Property") and LuxCo
and its Subsidiaries (such leased properties, individually, a "LuxCo Real
Property Lease," and the real properties specified in such leases being
referred to individually as an "LuxCo Property" and collectively as the "LuxCo
Properties" as respective lessees. Each of the Companies has made available
true and complete copies of the OmniUK Real Property Leases and the LuxCo Real
Property Leases. The OmniUK Property, LuxCo Property and OmniUK Owned Property
constitute all interests in real property currently used or currently held for
use in connection with the respective businesses of the Companies and their
respective Subsidiaries and which are necessary for the continued operation of
the respective businesses of the Companies and their respective Subsidiaries
as such businesses are currently conducted. Each OmniUK Real Property Lease
and LuxCo Real Property Lease is valid, binding, enforceable and in full force
and effect, except insofar as enforcement thereof may be limited by
bankruptcy, insolvency or other laws relating to or affecting enforcement of
creditors' rights generally including such general equitable principles as may
apply in the enforcement of creditors' rights. Each of the Companies and each
of their respective Subsidiaries has performed in all material respects all
obligations required to be performed by them, if any, under each OmniUK Real
Property Lease and LuxCo Real Property Lease. Other than the consents set
forth on the Summary (as herein defined), at Closing no event or conditions
will exist which will constitute or, after notice or lapse of time or both,
would constitute a default in any material respect on the part of the
Companies or any of their respective Subsidiaries under any such OmniUK Real
Property Lease or LuxCo Real Property Lease, as applicable. To each Company's
knowledge, each other party to each OmniUK Real Property Lease or LuxCo Real
Property Lease, as applicable, has in all material respects performed all
obligations required to be performed by it, and no event or condition exists
which constitutes or, after notice or lapse of time or both, would constitute
a default in any material respect on the part of such other party under any
such OmniUK Real Property Lease or LuxCo Real Property Lease, as applicable.
All of the OmniUK Properties, LuxCo Properties, buildings, fixtures and
improvements thereon owned or leased by the Companies or any of their
respective Subsidiaries are in good operating condition and repair (subject to
normal wear and tear).

     (b) Except as set forth on Schedule 2.12, the Companies and their
<PAGE>

respective Subsidiaries have all material certificates of occupancy and
material permits and licenses of any Governmental Entity necessary for the
current use and operation of the OmniUK Property, the LuxCo Property and the
OmniUK Owned Property, and the Companies and their respective Subsidiaries
have complied with all material conditions of such material permits and
licenses applicable to them. No default or violation, or event which, with the
lapse of time or giving of notice or both would become a default or violation,
has occurred in the due observance of any such material permit or license,
other than defaults or violations which, individually or in the aggregate,
would not be reasonably likely to have a Material Adverse Effect.

     (c) There does not exist any actual or, to the knowledge of each
Company, threatened or contemplated condemnation or eminent domain proceedings
that affect any of the OmniUK Property, the LuxCo Property, the OmniUK Owned
Property or any part thereof, and none of the Companies or any of their
respective Subsidiaries has received any written notice, of the intention of
any Governmental Entity or other Person to take or use all or any part
thereof.

     (d) None of the Companies or any of their respective Subsidiaries has
received any written notice from any insurance company that has issued a
policy with respect to any of the OmniUK Property, the LuxCo Property or the
OmniUK Owned Property requiring performance of any structural or other
substantial repairs or alterations to such OmniUK Property, LuxCo Property and
the OmniUK Owned Property.

     (e) Except as set forth on Schedule 2.12, none of the Companies or any of
their respective Subsidiaries owns or holds, and is not obligated under or a
party to, any option, right of first refusal or other contractual right to
purchase, acquire, sell, assign or dispose of any real estate or any portion
thereof or interest therein.

     (f) There is no actual or contingent liability on the part of either of
the Companies in relation to any real property other than as set forth on
Schedule 2.12 including any actual or contingent liability as previous lessee
or underlessee or guarantor or surety or covenant in relation to any Omni UK
Real Property Leases or LuxCo Real Property Leases.

     (g) There is no mortgage debt secured by Wyvol's Court, which is the only
UK Owned Property.

     Section 2.13 Contracts. Except as set forth in Schedule 2.13, neither of
the Companies nor any of their respective Subsidiaries is a party to or
otherwise bound by any:

     (a) employment, severance or consulting agreement, contract or other
arrangement;

     (b) covenant not to compete or covenant restricting the development,
marketing or distribution of the products and services of either of the
Companies or any of their respective Subsidiaries including without
limitation, franchise agreements providing for geographic or name exclusivity;

     (c) agreement, contract or other arrangement with (A) any stockholder of
either Company or any Affiliate (as defined herein) of any such stockholder or
(B) any current or former officer, director or employee of either of the
Companies or their respective Subsidiaries;

     (d) lease or similar agreement or other arrangement with any person under
which (A) either of the Companies or any of their respective Subsidiaries is
lessee of, or holds or uses, any machinery, equipment, vehicle or other
tangible personal property owned by any person or (B) either of the Companies
or any of their respective Subsidiaries is a lessor or sublessor of, or makes
available for use by any person, any tangible personal property owned or
leased by either of the Companies or any of their respective Subsidiaries, in
the case of either (A) or (B) which has an aggregate future liability or
receivable, as the case may be, of more than $100,000 individually or is not
terminable by such Company or any of such Company's Subsidiaries by notice of
more than 60 days for a cost of not more than $100,000 individually;

     (e) (A) continuing agreement, contract or other arrangement for the
future purchase of supplies or equipment, (B) management, service, consulting
or other similar type of agreement, contract or other arrangement or (C)
advertising agreement, contract or other arrangement, in the case of any of
(A), (B) or (C) which has an aggregate future liability to any person of more
than $100,000 individually or is not terminable by such Company or any of such
Company's Subsidiaries by notice of not more than 60 days for a cost of not
more than $100,000 individually;

     (f) license, option or similar agreement, contract or other arrangement
relating in whole or in part to intellectual property (including any license
or other agreement under which either of the Companies or any of their
respective Subsidiaries is licensee or licensor of any such intellectual
property) or to trade secrets, confidential information or proprietary rights
and processes of the either of Companies or any other person, in any such
case, which has an aggregate future liability or receivable, as the case may
be, of more than $100,000 individually or is not terminable by such Company or
any of such Company's Subsidiaries by notice of not more than 60 days for a
cost of not more than $100,000 individually;

     (g) except for the Notes and certain inter-company loans made between the
Companies and their Subsidiaries, agreement, contract or other instrument or
<PAGE>

arrangement under which either of the Companies or any of their respective
Subsidiaries has borrowed any money from, or issued any note, bond, debenture,
guarantee or other evidence of indebtedness to, any person in any such case
which has an aggregate future liability to any person of more than $100,000
individually or is not terminable by such Company or any of such Company's
Subsidiaries by notice of not more than 60 days for a cost of not more than
$100,000 individually;

     (h) except for certain inter-company loans made between the Companies and
their Subsidiaries, agreement, contract or other instrument or arrangement
under which either of the Companies or any of their respective Subsidiaries
has, directly or indirectly, made any advance, loan, extension of credit or
capital contribution to, or other investment in, any person in any such case
which has an aggregate future liability to any person of more than $100,000
individually or is not terminable by such Company or any of such Company's
Subsidiaries by notice of not more than 60 days for a cost of not more than
$100,000 individually;

     (i) agreement, contract or other instrument or arrangement providing for
indemnification of any person with respect to liabilities relating to any
current or former business of either of the Companies or any of their
respective Subsidiaries or any predecessor person in any such case which has
an aggregate future liability to any person of more than $100,000 individually
or is not terminable by such Company or any of such Company's Subsidiaries by
notice of not more than 60 days for a cost of not more than $100,000
individually; or

     (j) other agreement, contract or other arrangement to which either of the
Companies or any of their respective Subsidiaries is a party or by which they
or any of their respective properties or assets is bound which has an
aggregate future liability or receivable to or from any person of more than
$100,000 individually or is not terminable by such Company or any of such
Company's Subsidiaries by notice of not more than 60 days for a cost of not
more than $100,000 individually.

; provided, however, that notwithstanding anything to the contrary contained
herein other than any contracts relating to office equipment, maintenance or
service for any individual business center of the Companies or their
respective Subsidiaries which does not require annual payments in excess of
$25,000, the sum of the aggregate future liabilities and costs of termination
associated with all contracts, arrangements, agreements or understandings to
which either of the Companies or any of their respective Subsidiaries is a
party or by which they or any of their respective properties or assets which
are not set forth on Schedule 5.2, 2.13 or 2.16 is bound exceed $5,000,000.

     Except as set forth in Schedule 2.13, all agreements, contracts, leases,
subleases, licenses, options, instruments or arrangements of the Companies or
any of their respective Subsidiaries listed in the Schedules hereto
(collectively, "Contracts") are valid, binding and in full force and effect
and are enforceable by the respective Company which is a party to such
Contract and each of its Subsidiaries in accordance with its terms, except
insofar as enforcement thereof may be limited by bankruptcy, insolvency or
other laws relating to or affecting enforcement of creditors' rights generally
including such general equitable principles as may apply in the enforcement of
creditors' rights. Except as set forth in Schedule 2.13, the Companies and
their respective Subsidiaries have performed in all material respects all
obligations required to be performed by them to date under material Contracts
and none of the Companies or their respective Subsidiaries are (with or
without the lapse of time or the giving of notice, or both) in breach or
default in any material respect thereunder and, to each Company's knowledge,
no other party to any material Contracts is (with or without the lapse of time
or the giving of notice, or both) in breach or default in any material respect
thereunder.

     Section 2.14 Litigation. Except as set forth in Schedule 2.14, there is
no claim, action, suit, proceeding, arbitration, investigation or inquiry
before any Governmental Entity or any private arbitration tribunal now
pending, or, to the knowledge of each Company, threatened, against, relating
to or affecting either of the Companies or any of their respective
Subsidiaries or any of their respective properties, employees, assets or
business or the transactions contemplated by this Agreement. Except as set
forth in Schedule 2.14, to the knowledge of each Company, there is no basis
for any such claim, action, suit, proceeding, arbitration, investigation or
inquiry which, individually or in the aggregate, may reasonably be expected to
have a Material Adverse Effect. None of the Companies, any of their respective
Subsidiaries or any of their respective directors, officers or employees or
any of their respective Subsidiaries have been permanently or temporarily
enjoined or prohibited by judgment, order or decree of any Governmental Entity
from engaging in or continuing any conduct or practice in connection with the
businesses engaged in by the Companies and their respective Subsidiaries. None
of the Companies is operating under, subject to or in default with respect to
any judgment, order or decree of any Governmental Entity enjoining or
prohibiting either of the Companies or any of their respective Subsidiaries
from taking, or requiring either of the Companies or any of their respective
Subsidiaries to take, any action of any kind or to which either of the
Companies or any of their respective Subsidiaries or any of their respective
properties or assets is subject or bound.

     Section 2.15 Insurance. Schedule 2.15 lists all policies of fire and
casualty, liability and other forms of insurance maintained or held by each of
the Companies or any of their respective Subsidiaries, which policies are in
such amounts, and with such deductibles and which insure against such risks
<PAGE>

and losses as are customary for the businesses conducted by the Companies and
their respective Subsidiaries. All such policies are in full force and effect
and are sufficient for compliance by each of the Companies and their
respective Subsidiaries with all their respective agreements, all premiums due
and payable thereon have been paid (other than retroactive or retrospective
premium adjustments that are not yet, but may be, required to be paid with
respect to any period ending prior to the Closing Date), and no notice of
cancellation or termination has been received with respect to any such policy
which has not been replaced on substantially similar terms prior to the date
of such cancellation. The activities and operations of each of Companies and
their respective Subsidiaries have been conducted in a manner so as to conform
in all material respects to all applicable provisions of such insurance
policies.

     Section 2.16 Benefit Plans.

     (a) Schedule 2.16 sets forth a list and brief description of all
retirement, health, life fringe benefit, severance or similar employee benefit
arrangements (all the foregoing being herein called "Benefit Plans")
maintained by each of the Companies or any of their respective Subsidiaries
for the benefit of any director, officer or employee of any of the Companies
or their respective Subsidiaries. Each of the Companies has made available to
VANTAS true, complete and correct copies of each Benefit Plan.

     (b) Each Benefit Plan has been administered in all material respects in
accordance with its terms. Each of the Companies, their respective
Subsidiaries and all the Benefit Plans are in compliance in all material
respects with the applicable provisions of applicable law, and all employer
and employee contributions have been timely made under such Benefit Plans.
There are no lawsuits, actions, termination proceedings or other formal
proceedings pending, or, to the knowledge of each Company, threatened against
or involving any Benefit Plan and, to the knowledge of each Company, there are
no investigations by any Governmental Entity or other claims (except claims
for benefits payable in the normal operation of the Benefit Plans) pending or
threatened against or involving any Benefit Plan or asserting any rights to
benefits under any Benefit Plan.

     (c) None of the Benefit Plans provide for post-retirement medical or
dental insurance benefits, the cost of which is not entirely borne by the
retirees eligible therefor.

     (d) Except as set forth in Schedule 2.16, no director, officer or
employee or former director, officer or employee of either the Companies or
their respective Subsidiaries will become entitled to payment or accelerated
vesting of any bonus, retirement, severance, job security or similar benefit
or any enhanced benefit solely as a result of the transactions contemplated
hereby.

     Section 2.17 Compliance with Applicable Laws. Each of the Companies and
their respective Subsidiaries are in compliance in all material respects with
all applicable statutes, laws, ordinances, rules, orders and regulations of
any Governmental Entity ("Applicable Laws"). Except as set forth in Schedule
2.17, none of the Companies or any of their respective Subsidiaries has
received any written communication during the past two years from a
Governmental Entity that alleges that either of the Companies or any of their
respective Subsidiaries are not in compliance in any material respect with any
Applicable Laws.

     Section 2.18 Labor Matters. (i) Except as disclosed on Schedule 2.18:

          (i)     neither of the Companies nor any of their respective
     Subsidiaries is a party to any labor or collective bargaining agreement
     with respect to its employees; no employees of either of the Companies or
     any of their respective Subsidiaries are represented by any labor
     organization; no labor organization or group of employees of either of
     the Companies or any of their respective Subsidiaries has made a pending
     demand for recognition or certification to either of the Companies or any
     of their respective Subsidiaries; and there are no representation or
     certification proceedings or petitions seeking a representation
     proceeding presently pending or, to the knowledge of each Company,
     threatened, to be brought or filed with the National Labor Relations
     Board or other labor relations tribunal involving either of the Companies
     or any of their respective Subsidiaries;

          (ii)    there are no strikes, lockouts, work stoppages or slowdowns
     pending or, to the knowledge of each of the Companies, threatened against
     or involving either of the Companies or any of their respective
     Subsidiaries;

          (iii)   there are no unfair labor practice charges, arbitrations or
     grievances pending or threatened in writing against or involving either
     of the Companies or any of their respective Subsidiaries relating to the
     employment or termination of employment of any individual by either of
     the Companies or any of their respective Subsidiaries;

          (iv)    there are no complaints, charges or claims against either of
     the Companies or any of their respective Subsidiaries pending or, to the
     knowledge of each of the Companies or any of their respective Subsidiaries,
     threatened in writing to be brought or filed with any Governmental Entity
     based on or arising out of the employment by the Companies of any employee;

          (v)     the Companies and each of their respective Subsidiaries are in
<PAGE>

     compliance in all material respects with all laws relating to the
     employment of labor, including all such Laws relating to wages, hours,
     collective bargaining, discrimination, civil rights, safety and health,
     workers' compensation and the collection and payment of withholding
     and/or Social Security Taxes and similar Taxes; and

          (vi)    none of the Companies or any of their respective
     Subsidiaries is a party to, or otherwise bound by, any consent decree with,
     or citation by, any Governmental Entity relating to employees or employment
     practices.

     Section 2.19 Transactions with Affiliates. Except as set forth in
Schedule 2.19 and excluding the Notes, (i) none of the Contracts between
either of the Companies and/or any of their respective Subsidiaries, on the
one hand, and any Affiliate of either such Company, on the other hand, will
continue in effect subsequent to the Closing, (ii) after the Closing no
Affiliate of either of the Companies will have any interest in any property
(real or personal, tangible or intangible) or contract used in or pertaining
to the business of such Company, and (iii), no Affiliate of either of the
Companies has any direct or indirect ownership interest in any person in which
either of the Companies and/or their respective Subsidiaries has any direct or
indirect ownership interest. As used herein the term "Affiliate" shall mean,
with respect to any Person, (i) any Person directly or indirectly controlling,
controlled by or under common control with such Person, or (ii) any officer,
director, general partner, managing member or trustee of such Person or any
Person referred to in clause (i) above. For purposes of this definition of
Affiliate, "control," when used with respect to any Person, means the power to
direct the management and policies of such Person, directly or indirectly,
whether through the ownership of voting securities, by contract or otherwise,
and the terms "controlling" and "controlled" have meanings correlative to the
foregoing.

     Section 2.20 Corporate Name. Schedule 2.22 sets out the rights of OmniUK,
LuxCo and their respective subsidiaries in "OmniOffices", "HQ", "Lambert Smith
Hampton", "Lambert Smith Hampton Group Limited" and "Offices in the City of
Vienna" and none of the Companies and their respective Subsidiaries has
received any notice of conflict during the past two years with respect to the
rights of others regarding such names. LuxCo has the exclusive right in
Luxembourg to use the name "OmniOffices (Lux) 1929 Holding Company S.A. Except
as set forth in Schedule 2.22, no person (other than each of the Companies and
their respective Subsidiaries) is authorized by either of the Companies to
use, or otherwise has the right to use, the names in England, Germany, Austria
and Luxembourg.

     Section 2.21 Customers. Except for the Persons leasing or otherwise
having rights to occupy those properties subject to real property leases
(collectively, the "Customers") set forth in Schedule 2.21, neither of the
Companies nor their respective Subsidiaries have any Customer from which any
received more than 2% of its respective revenues during their most recent full
fiscal year. Since the date of the respective Balance Sheets, there has not
been any material adverse change in the business relationships of either of
the Companies and their respective Subsidiaries with any Customers set forth
in Schedule 2.21.

     Section 2.22 Intellectual Property. (a) Except as set forth on Schedule
2.22, each of the Companies has good title to or the right to use all material
copyrights, patents, trademarks (registered or unregistered), trade names and
service marks and applications therefor and other material intellectual
property and proprietary rights, whether or not subject to statutory
registration or protection, necessary for the conduct of any of their
respective businesses as currently conducted (collectively, "Intellectual
Property"). Schedule 2.22 sets forth a list of the registered and unregistered
trademarks owned or used by each of the Companies and all jurisdictions in
which such trademarks are registered or applied for and all registration and
application numbers. Except as set forth in Schedule 2.22, the consummation of
the transactions contemplated hereby will not conflict with, alter or impair
any such rights.

     (b) Except as set forth on Schedule 2.22, neither the Companies nor any
of their respective Subsidiaries has granted any options, licenses or
agreements of any kind relating to Intellectual Property listed in Schedule
2.22 or the marketing or distribution thereof. Neither of the Companies nor
any of their respective Subsidiaries is bound by or a party to any options,
licenses or agreements of any kind relating to the Intellectual Property of
any other person, except as set forth in Schedule 2.22 and except for
agreements relating to computer software licensed to any of the Companies or
any of their respective Subsidiaries in the ordinary course of business.
Subject to the rights of third parties set forth in Schedule 2.22, all
Intellectual Property is free and clear of the claims of others and of all
liens, security interests and encumbrances whatsoever. The conduct of the
business of each of the Companies as presently conducted does not violate,
conflict with or infringe the intellectual property of any other person except
where such infringement would not have a Material Adverse Effect. Except as
set forth in Schedule 2.22, (i) no claims are pending, or to the knowledge of
each Company, threatened, against either of the Companies by any person with
respect to the ownership, validity, enforceability, effectiveness or use of
any Intellectual Property and (ii) during the past two years neither of the
Companies have received any communications alleging that the Companies or any
of their respective Subsidiaries has violated any rights relating to
intellectual property of any Person.

     Section 2.23 Environmental Liability.
<PAGE>

     For purposes of this Section 2.23, the following definitions shall apply:

     In this paragraph, where the context admits--

     "Environment" means air (including, without limitation, that within
     buildings or natural or man-made structures, whether above or below
     ground), water (including, without limitation, inland fresh waters and
     ground waters as defined in Section 104(1)(d) of the Water Resources Act
     1991) and land (including, without limitation, soil and river beds under
     any water as described above, surface land and sub-surface land) and all
     other matter and energy, in whatever form, state, compositions or
     combinations, at whatever level and in or under whatever forces, systems,
     cycles or other conditions occurring (whether as elements or compounds,
     whether as radioactivity, heat, light, sound or other electromagnetic
     radiation or wave forms, whether in solid, liquid or gaseous state,
     whether in animal, vegetable, mineral, organic or inorganic forms and
     whether in a state of equilibrium or reactivity) anywhere in, on, around
     or affecting the world or any part of it (including without limitation
     its atmosphere and orbital path);

     "Hazardous Substance" means any waste and/or any substance (whether
     solid, liquid, gas, noise, ion, vapour, electromagnetic or radiation)
     which alone or in combination with any other substance is hazardous,
     toxic, radioactive, explosive or capable of polluting, damaging or
     otherwise adversely affecting or impairing the Environment or causing
     harm to the health, well-being or existence (now or in the future) of any
     human being or any other living organism;

     "Permit" means any consent, approval, authorisation, exemption, licence,
     order or permission;

     "Relevant Law" means a requirement of or duty imposed by international
     law, EU law, the common law, United Kingdom legislation and subordinate
     or delegated legislation, a judgement, order or award of any court, or
     European Community regulations or directives having the force of law in
     the United Kingdom, which in any case relate to the protection of the
     Environment (or any part of it), the control of discharges or emissions,
     the prevention of harm to or impairment of the health, well-being or
     existence (now or in the future) of any human being or of any other
     living organism, or to the storage, disposal, handling or transport of
     any Hazardous Substance.

     (a) To the knowledge of the Companies, except as set forth or referred to
in Schedule 2.23 no allegation or claim of any violation or failure to comply
with the requirements of any Relevant Law has been received by either of the
Companies or any of their respective Subsidiaries and to the knowledge of the
Companies there are no circumstances which might give rise to such a claim.
Except as set forth or referred to in Schedule 2.23, the Company has not
received any notice of equivalent nature, or any judgement, order, decree,
award, demand or decision in respect of the Environmental from any court,
tribunal, arbitrator or governmental or regulatory authority and to the
knowledge of the Companies there have been no complaints, investigations,
enquiries, requests for information or other indications of any possible
claims or legal actions in respect of the Environment from any Person.

     (b) To the knowledge of the Companies and except as set forth or referred
to in Schedule 2.23 during or prior to the period of its or any of its
Subsidiaries' ownership or operation of their respective current properties
there were no releases or threatened releases of Hazardous Substances in or
under or affecting any such property.

     (c) Except as set forth or referred to in Schedule 2.23, each of the
Companies and their respective Subsidiaries has obtained all material Permits
required by all Relevant Laws in relation to the conduct of its business and
has complied with the material terms of the such Permits in all material
respects.

     Section 2.24 Brokers. No brokers or finders that have acted for
CarrAmerica in connection with this Agreement except for Goldman Sachs & Co.

     Section 2.25 Competition. Neither of the Companies has been nor is it
concerned in any agreements or arrangements which infringed or infringes or
which have or should have been registered under or which have or to the
Companies' knowledge may become the subject of any reference, inquiry,
proceeding, report, assurance or undertaking under or in respect of the
Restrictive Trade Practices Acts 1976 and 1977, the Fair Trading Act 1973,
Article 81, 82, 85 or Article 86, if applicable, of the Treaty of Rome, the
Competition Act 1980, the Competition Act 1998 or any other anti-trust,
anti-restrictive practice or similar legislation within the United Kingdom and
neither of the Companies has made or, to each of the Companies' knowledge,
threatened to make any complaint against any other person to any relevant
authority under any law or legislation referred to in this paragraph.

     Section 2.26 Data Protection. Except as set forth in Schedule 2.17,
the Companies and each of their Subsidiaries hold all necessary United Kingdom
data protection registrations as required under United Kingdom legislation in
respect of all personal data (as that expression is defined in the United
Kingdom data protection legislation) other than those the absence of which
would have Material Adverse Effect.

     Section 2.27 Equivalence. For the purpose of construction, the references
<PAGE>

in the representations and warranties contained herein to (i) any statutory
provision enacted, or accounting principles applying, in the United States
shall be deemed to include references to any corresponding provision in the
local legislation and (where relevant) to generally accepted accounting
principles applying in the country or state of incorporation, (ii) any
governmental or administrative authority or agency shall be deemed to include
references to the equivalent federal state or local governmental or
administrative authority or agency; and (iii) certificates of incorporations
or by-laws shall be deemed to include references to the equivalent documents
(including memoranda and articles of association or statutes) which describe
the governance of the Companies.

     Section 2.28 MAM Investment. OmniUK and certain of its Subsidiaries have
agreed to invest up to Lire 20 million in Mercury Executive Offices, L.P. on
the terms and conditions set forth in the limited partnership agreement, dated
November 16, 1998 (the "MAM Investment"), of which at least Lire 15,594,241
has been funded. So long as VANTAS satisfies its obligations under Section
5.4, no consent is necessary under the Limited Partnership Agreement, dated 16
November, 1998, constituting the Mercury Executive Offices, L.P. or the
Management Agreement with respect thereto, in order to maintain such contracts
or arrangements in full force and effect following the Closing.

     Section 2.29 Contingent Payments. Except as set forth in Section 5.3,
there are no contingent payment obligations or "earn-outs" which are or may
become payable in connection with center acquisitions made by the Companies or
any of their respective Subsidiaries prior to the date of this Agreement.

     (B) CarrAmerica hereby represents and warrants to VANTAS as follows:

     Section 2.1 Authority. CarrAmerica has all requisite corporate power and
authority to enter into this Agreement, to perform its obligations hereunder
and to consummate the transactions contemplated hereby. All acts and other
proceedings required to be taken by CarrAmerica to authorize the execution,
delivery and performance of this Agreement and the consummation of the
transactions contemplated hereby have been duly and properly taken. This
Agreement has been duly executed and delivered by a duly authorized officer of
CarrAmerica and constitutes a legal, valid and binding obligation of
CarrAmerica, enforceable against CarrAmerica in accordance with its terms
except insofar as enforcement thereof may be limited by bankruptcy, insolvency
or other laws relating to or affecting enforcement of creditors' rights
generally including such general equity principles as may apply in the
enforcement of creditors' rights.

     Section 2.2. No Conflicts; Consents. The execution and delivery of this
Agreement by CarrAmerica does not, and the consummation of the transactions
contemplated hereby and compliance by CarrAmerica with the terms hereof will
not, conflict with, or result in any violation of or default (with or without
notice or lapse of time, or both) under, or give rise to a right of
termination, cancellation or acceleration of any obligation or to material
loss of a benefit under, or result in the creation of any lien, charge or
encumbrance of any kind upon any of the properties or assets of such Seller
under, any provision of (i) the certificate of incorporation or by-laws (or
equivalent organizational document) of CarrAmerica, (ii) any material note,
bond, mortgage, indenture, deed of trust, loan document, license, lease,
contract, commitment, agreement or arrangement to which CarrAmerica is a party
or by which CarrAmerica or any of its properties or assets is bound or (iii)
any judgment, order or decree, or statute, law, ordinance, rule or regulation,
applicable to CarrAmerica or any of its properties or assets. No consent,
approval, license, permit, order or authorization of, or registration,
declaration or filing with, any Federal, state, local or foreign government or
any court of competent jurisdiction, administrative agency or commission or
other governmental authority or instrumentality, domestic or foreign, or any
national securities or commodities exchange or other regulatory or
self-regulatory body or association is required to be obtained or made by or
with respect to CarrAmerica in connection with the execution, delivery and
performance of this Agreement by CarrAmerica or the consummation of the
transactions contemplated hereby, other than compliance with any filings under
the HSR Act.

                                  ARTICLE III

                   Representations and Warranties of VANTAS

         VANTAS hereby represents and warrants to CarrAmerica as follows:

     Section 3.1 Organization and Standing. VANTAS is duly organized, validly
existing and in good standing under the laws of the State of Delaware; has all
requisite power and authority necessary to carry on its business as presently
conducted and to enable it to own, lease or otherwise hold its properties and
assets; and is duly qualified to do business and is in good standing in each
jurisdiction in which the conduct or nature of its business or the ownership,
leasing or holding of its properties or assets makes such qualification
necessary, except such jurisdictions where the failure to be so qualified or
in good standing, individually or in the aggregate, would not have a material
adverse effect on the business, financial condition or results of operations
of VANTAS and its Subsidiaries, taken as a whole.

     Section 3.2 Authority. VANTAS has all requisite corporate power and
authority to enter into this Agreement, to perform its obligations hereunder
to consummate the transactions contemplated hereby. All acts and other
proceedings required to be taken by VANTAS to authorize the execution,
delivery and performance of this Agreement and the consummation of the
<PAGE>

transactions contemplated hereby have been duly and properly taken. This
Agreement has been duly executed and delivered by a duly authorized officer of
VANTAS and constitutes a legal, valid and binding obligation of VANTAS,
enforceable against VANTAS in accordance with its terms except insofar as
enforcement thereof may be limited by bankruptcy, insolvency or other laws
relating to or affecting enforcement of creditors' rights generally including
such general equity principles as may apply in the enforcement of creditors'
rights.

     Section 3.3 No Conflicts; Consents. The execution and delivery of this
Agreement by VANTAS does not, and the consummation of the transactions
contemplated hereby and compliance by VANTAS with the terms hereof will not,
conflict with, or result in any violation of or default (with or without
notice or lapse of time, or both) under, or give rise to a right of
termination, cancellation or acceleration of any obligation or to a material
loss of a benefit under, or result in the creation of any lien, charge or
encumbrance of any kind upon any of the properties or assets of VANTAS under,
any provision of (i) the Certificate of Incorporation or By-Laws of VANTAS,
(ii) any material note, bond, mortgage, indenture, deed of trust, loan
document, license, lease, contract, commitment, agreement or arrangement to
which VANTAS is a party or by which it or any of its properties or assets is
bound or (iii) any judgment, order or decree, or statute, law, ordinance, rule
or regulation, applicable to VANTAS or any of its properties or assets. No
consent, approval, license, permit, order or authorization of, or
registration, declaration or filing with, any Governmental Entity is required
to be obtained or made by or with respect to VANTAS in connection with the
execution, delivery and performance of this Agreement by VANTAS or the
consummation of the transactions contemplated hereby, other than compliance
with any filings under the HSR Act.

                                  ARTICLE IV

                        Agreements of OMNI UK and LuxCo

     Section 4.1 Each of Omni UK and LuxCo and, as applicable, CarrAmerica
covenants and agrees as follows:

     (a) Access. Prior to the Closing, the Companies shall, and shall cause
their respective Subsidiaries to, give VANTAS and its respective officers,
employees, representatives, counsel financing sources and accountants and
their respective counsel, auditors and authorized representatives full access,
during normal business hours and upon reasonable notice, to the personnel,
properties, financial statements, contracts, books, records, working papers
and other relevant information pertaining thereto each of the Companies and
their respective Subsidiaries and shall request and use commercially
reasonable efforts to cause their respective employees, counsel, auditors and
financial advisors to cooperate with VANTAS in their preparation of any rating
agency presentation materials, private placement prospectus or offering
memorandum, syndication book or similar marketing materials ("Financing
Materials") in connection with a transaction to sell securities of HQ in
connection with the HQ Merger or obtain a credit facility to finance VANTAS'
obligations pursuant to this Agreement and RSI's obligations pursuant to the
Stock Purchase Agreement and in their investigation of the businesses of each
of the Companies and their respective Subsidiaries on a consolidated basis,
including by furnishing copies of data or information pertaining to the
businesses of the Companies and their respective Subsidiaries for purposes of
due diligence or, with the prior written approval of CarrAmerica, which
approval will not be reasonably withheld, for inclusion in any Financing
Materials in connection with a transaction to sell securities of HQ in
connection with the HQ Merger or obtain a bank credit facility to finance
VANTAS's obligations pursuant to this Agreement and RSI's obligations pursuant
to the Stock Purchase Agreement. Prior to the Closing, the Companies shall,
and shall cause their respective Subsidiaries, officers and employees to,
furnish to VANTAS and its respective officers, employees, representatives,
counsel and accountants such financial, tax and operating data and other
information with respect to the business, properties and assets of each of the
Companies and their respective Subsidiaries as VANTAS or any such person shall
from time to time reasonably request, and the Companies shall, and shall cause
their respective Subsidiaries, directors, officers and employees to, cooperate
with, and the Companies shall request their respective independent public
accountants and independent legal counsel to cooperate with, VANTAS and its
respective officers, employees, representatives, counsel and accountants so as
to enable VANTAS to be kept fully informed with respect to the business,
assets, financial condition, results of operations and prospects of the
Companies.

     (b) Ordinary Conduct. Except as set forth in the capital expenditure and
operating budgets (the "CapEx Budgets") of each of the Companies attached
hereto as part of Schedule 4.1(b) or otherwise expressly permitted by the
terms of this Agreement, from the date hereof to the Closing, the Companies
and each of their respective Subsidiaries shall continue to conduct their
business in the ordinary course in substantially the same manner as presently
conducted and shall make all reasonable efforts consistent with past practices
to preserve their respective relationships with customers and others with whom
they deal. The Companies and their respective Subsidiaries shall not take any
action that would, or that could reasonably be expected to, result in (A) any
of the representations and warranties (including, but not limited to, those
set forth in Article II) of the Companies set forth in this Agreement that are
qualified as to materiality becoming untrue or incorrect, (B) any of such
representations and warranties that are not so qualified becoming untrue or
incorrect in any material respect or (C) any of the conditions to the Closing
set forth in Section 6.3 not being satisfied. In addition, except as set forth
<PAGE>

in the CapEx Budgets or Schedule 4.1(b) or otherwise expressly permitted by
the terms of this Agreement, each of the Companies and their respective
Subsidiaries shall not do any of the following without the prior written
consent of VANTAS:

          (i)     adjust, split, combine or reclassify any of their respective
     capital stock; make, declare or pay any dividend or make any other
     distribution on, or directly or indirectly redeem, purchase or otherwise
     acquire, any shares of its capital stock, membership or partnership
     interests or any securities or obligations convertible into or
     exchangeable for any shares of their respective capital stock or
     membership or partnership interests; issue, deliver or sell any shares of
     its capital stock or membership or partnership interests or any
     securities convertible into or exercisable for, or any rights, options or
     warrants to acquire, any such shares or securities (whether for cash or
     property) to any person;

          (ii)    sell, lease, transfer or otherwise dispose of, or subject to
     any Lien, any of their respective properties or assets, or cancel, release
     or assign any material indebtedness owed to either of the Companies or any
     material claim held by either of the Companies, except (i) in bona fide
     arm's length transactions made in the ordinary course of business
     consistent with past practice or (ii) pursuant to contracts or agreements
     in force as of the date of this Agreement and listed in Schedule 2.13;

          (iii)   incur or assume any liabilities or incur any indebtedness for
     borrowed money, assume, guarantee, endorse or otherwise as an
     accommodation become responsible for the obligations of any other
     individual, corporation or entity (other than a wholly owned Subsidiary)
     except pursuant to contracts or agreements listed in Schedule 2.13 or
     except for loans by CarrAmerica necessary to fund the business of the
     Companies in the ordinary course or to fund committed developments;

          (iv)    make any material acquisition or investment either by purchase
     of stock or securities, merger or consolidation, contributions to
     capital, property transfers, or purchases of any property or assets of
     any other individual, corporation or other entity except pursuant to
     contracts or agreements in force as of the date of this Agreement and
     listed in Schedule 2.13;

          (v)     make any material change in any Omni UK Real Property Lease or
     LuxCo Real Property Lease, as applicable, or other contracts or enter
     into, renew, fail to renew, terminate or permit to be terminated any Omni
     UK Real Property Lease or LuxCo Real Property Lease, as applicable, any
     other contract or agreement that calls for aggregate annual payments of
     $25,000 or more and which either (i) is not terminable by either of the
     Companies or their respective Subsidiary, as applicable, at will on 60
     days or less notice without payment of a penalty or (ii) has a term of
     more than six months;

          (vi)    except in the ordinary course of business consistent with past
     practices (but in no event greater than 10% with respect to any
     employees), increase the compensation or fringe benefits of any of their
     respective employees or pay any bonus, pension or retirement allowance
     not required by any existing plan or agreement to which any such
     employees become a party, materially amend or commit themselves to any
     pension, retirement, profit-sharing or welfare benefit plan or agreement
     or employment agreement with or for the benefit of any employee or
     accelerate the vesting of any stock options or other stock-based
     compensation except for accelerations required by any existing plan or
     agreement set forth on Schedule 2.16;

          (vii)   other than with respect to the MAM Investment, make any loans,
     advances or capital contributions to any other person, other than loans
     and advances to their respective Subsidiaries;

          (viii)  make any capital expenditures in excess of (A) $25,000
     individually or (B) $100,000 in the aggregate, other than expenditures
     necessary to maintain existing assets in good repair not to exceed in the
     aggregate $250,000;

          (ix)    Intentionally Omitted;

          (x)     settle any claim, action or proceeding involving money damages
     except in the ordinary course of business consistent with past practice
     for settlements for monetary damages that in any event do not,
     individually or in the aggregate with any other such settlements, exceed
     $100,000; provided, however, that notwithstanding the foregoing, in no
     event may either of the Companies settle such claim, action or proceeding
     without VANTAS' prior written consent if such settlement imposes any
     ongoing duties, obligations or liabilities on the Companies which can
     reasonably be expected to require either of the Companies to incur
     liabilities in excess of $100,000 or unduly impair the conduct of either
     of the Companies' business;

          (xi)    Intentionally Omitted;

          (xii)   amend their respective Certificates of Incorporation, By-laws
     or similar governing documents, as the case may be;

          (xiii)  enter into any new line of business;
<PAGE>

          (xiv) enter into or perform any commitment, contractual obligation,
     borrowing, capital expenditure or other transaction (except pursuant to the
     Notes or agreements in force as of the date of this Agreement and listed on
     Schedule 2.13) with any officer, director, consultant or Affiliate of
     either of the Companies or any of their respective Subsidiaries;

          (xv)  make any changes in their respective accounting methods, except
     as may be required under law, rule, regulation or generally accepted
     accounting principles in the jurisdiction of incorporation of the
     applicable Company, in each case as concurred in by such party's
     independent public accountants; or

          (xvi) agree to, or make any commitment to, do any of the foregoing.

     Each of the Companies recognizes that the agreements contained in this
Section 4.1(b) are an integral part of the transactions contemplated by this
Agreement and that without these agreements, VANTAS would not enter into this
Agreement; accordingly, in the event of the breach by either of the Companies of
the terms of this Section 4.1(b), VANTAS shall be entitled, if it so elects, to
institute and prosecute proceedings in any court of competent jurisdiction, to
enforce the specific performance thereof by either of the Companies, to enjoin
either of the Companies from actions or omissions in violation of this Section
4.1(b) or to otherwise obtain preliminary injunctive relief (without the
necessity to post a bond) from such actions or omissions.

     (c) Confidentiality. Each of the Companies shall keep all information
provided to it or any of its representatives pursuant to this Agreement
confidential, and each of the Companies shall not disclose such information to
any Persons other than the directors, officers, employees, financial advisors,
legal advisors, accountants and consultants of the respective Companies who
reasonably need to have access to the confidential information and (i) in the
case of directors, officers, employees, legal advisors and the principal
accountants of each of the Companies, who are advised of the confidential nature
of such information, and (ii) in the case of any financial advisors, other
accountants or consultants of each of the Companies, who execute an agreement
with VANTAS agreeing to maintain confidentiality of such information; provided,
however, the foregoing obligation of each of the Companies shall (A) not relate
to any information that (i) is or becomes generally available other than as a
result of unauthorized disclosure by each of the Companies or by Persons to whom
each of the Companies has made such information available, or (ii) is or becomes
available to each of the Companies on a non-confidential basis from a third
party that is not, to either of the Companies' knowledge, bound by any other
confidentiality agreement with VANTAS or (B) prohibit disclosure of any
information of each of the Companies believes in good faith that disclosure is
required by law, rule, regulation, court order or other legal or governmental
process (including SEC or GAAP reporting requirements) or if each of the
Companies believes in good faith that disclosure is advisable to explain a
material deviation from either of the Companies' expected financial results that
arises from the transactions contemplated hereby; provided, further that in the
case of a disclosure described in clause (B) above, each of the Companies shall
(i) give prior notice to VANTAS of any such disclosure and (ii) consult with
VANTAS prior to making such disclosure. Notwithstanding anything to the contrary
contained herein, the covenant of VANTAS set forth in this Section 4.1(c) shall
terminate 3 years after the Closing Date.

     (d) Supplemental Disclosure. Each of the Companies shall give prompt
notice to VANTAS of (i) any representation or warranty made by either of the
Companies, contained in this Agreement that is qualified as to materiality
becoming untrue or inaccurate or any such representation or warranty that is
not so qualified becoming untrue or inaccurate in any material respect or (ii)
the failure by either of the Companies to comply with or satisfy in any
material respect any covenant, agreement or condition to be complied with or
satisfied by either of the Companies under this Agreement; provided, however,
that no such notification shall affect the representations, warranties,
covenants or agreements of the parties or the conditions to the obligations of
the parties under this Agreement.

     (e) Summaries. Not later than two weeks prior to the Closing Date,
CarrAmerica shall deliver to VANTAS a true and accurate summary (the "Summary")
of the OmniUK Real Property Leases and the LuxCo Real Property Leases indicating
for each such lease (i) location, (ii) rent, (iii) term, (iv) square footage of
space demised thereunder, and (v) whether or not the consent of the landlord is
required in order for VANTAS to be able to succeed to the rights of the tenant
under such OmniUK Real Property Lease and LuxCo Real Property Lease.

                                   ARTICLE V

                               Mutual Covenants

     Section 5.1 Consummation of the Transactions. Subject to the terms and
conditions of this Agreement, each party shall use its commercially reasonable
efforts to cause the Closing to occur upon the terms and conditions hereof.
CarrAmerica and the Companies shall cooperate with VANTAS, and VANTAS shall
cooperate with CarrAmerica and the Companies, in filing any necessary
applications, reports or other documents with, giving any notices to, and
seeking any consents from, all Governmental Entities and all third parties as
may be required in connection with the consummation of the transactions
contemplated by this Agreement.
<PAGE>

     Section 5.2 Publicity. From the date of the execution and delivery of this
Agreement through the Closing, no public release or announcement concerning the
transactions contemplated hereby shall be issued by any party hereto without the
prior consent of (i) VANTAS in the case of a release or an announcement by
CarrAmerica or (ii) CarrAmerica in the case of a release or an announcement by
VANTAS (in each case which consent shall not be unreasonably withheld), except
as such release or announcement may be required by law or the rules or
regulations of any United States or foreign securities exchange, in which case
the party required to make the release or announcement shall, if practicable,
allow VANTAS or CarrAmerica, as the case may be, reasonable time to comment on
such release or announcement in advance of such issuance.

     Section 5.3 Payment for and Assumption of the Loan Notes. At the Closing,
CarrAmerica will assume the obligations under those certain loan notes dated as
of May 15, 1998 and January 8, 2000 (the "Loan Notes"), and concurrently
therewith, VANTAS shall pay CarrAmerica an amount equal to $21,229,327 (reduced
by the amount of any payments thereon prior to Closing). At Closing, the parties
shall enter into an assumption agreement in the form and substance reasonably
acceptable to the parties hereto (the "Assumption Agreement"). At Closing,
CarrAmerica shall deliver to VANTAS collateral reasonably satisfactory to VANTAS
to secure CarrAmerica's obligations under the Assumption Agreement which
collateral shall be released at such time as VANTAS is released from the
obligation or at the time such obligation is satisfied or expires.

     Section 5.4 MAM Investment. Prior to Closing, RSI shall execute a
replacement letter(s) of undertaking to replace that certain letter(s) of
undertaking delivered by CarrAmerica to the MAM in connection with its
investment in MAM.

     Section 5.5 Brook Street or Hammersmith Collateral. At the Closing, RSI
shall provide $922,530 to OmniUK to replace the cash or certificate of deposit
securing OmniUK's reimbursement obligation to Barklays Bank with respect to a
letter of credit securing the Brook Street or Hammersmith lease, as applicable,
and OmniUK shall pay such funds to Carr America at the Closing.

                                  ARTICLE VI

                             Conditions to Closing

     Section 6.1 Each Party's Obligation. The respective obligation of each
party hereto to effect the transactions contemplated hereby is subject to the
satisfaction or waiver of the following conditions: (i) no statute, rule,
regulation, executive order, decree, temporary restraining order, preliminary or
permanent injunction or other order shall have been enacted, entered,
promulgated, enforced or issued by any Governmental Entity that prohibits the
purchase and sale of the Shares or the Notes or any of the other material
transactions contemplated by this Agreement and (ii) no action, claim,
proceeding or investigation shall be pending or threatened by any Governmental
Entity (other than a court acting in response to an action, claim or proceeding
by a non-Governmental Entity) that, if successful, would result in any of the
foregoing effects.

     Section 6.2 CarrAmerica's Obligation. The obligations of CarrAmerica to
sell and deliver the Shares and the Notes to VANTAS and assume the Loan Notes
are subject to the satisfaction (or waiver by CarrAmerica) as of the Closing of
the following conditions:

     (a) The representations and warranties of VANTAS made in this Agreement
shall be true and correct as of the date hereof and as of the time of the
Closing as though made as of such time, except to the extent such
representations and warranties expressly relate to an earlier date (in which
case such representations and warranties shall be true and correct on and as of
such earlier date) and VANTAS and RSI shall have duly performed, complied with
and satisfied in all material respects all covenants, agreements and conditions
required by this Agreement to be performed, complied with or satisfied by VANTAS
or RSI, as applicable, by the time of Closing, except where the failure of such
representations and warranties to be true and correct and/or the failure to
perform, comply with and satisfy such covenants, agreements and conditions would
not constitute a Company Transaction Value Impairment. VANTAS and RSI shall have
delivered to CarrAmerica a certificate dated the Closing Date and signed by an
officer of each of VANTAS and RSI confirming the foregoing.

     (b) VANTAS shall have delivered to CarrAmerica the cash required by
Sections 1.2 and 5.3.

     (c) The HQ Merger shall have been consummated immediately prior to the
Closing hereunder.

     Section 6.3 VANTAS' Obligation. The obligation of VANTAS to purchase the
Shares and the Notes from CarrAmerica is subject to the satisfaction (or waiver
by VANTAS) as of the Closing of the following conditions:

     (a) The representations and warranties of CarrAmerica made in this
Agreement shall be true and correct, as of the time of the Closing as though
made as of such time, except to the extent such representations and warranties
expressly relate to an earlier date (in which case such representations and
warranties shall be true and correct on and as of such earlier date), and each
of CarrAmerica and the Companies shall have duly performed, complied with and
satisfied in all material respects all covenants, agreements and conditions
required by this Agreement to be performed, complied with or satisfied by
<PAGE>

CarrAmerica and/or the Companies, as applicable, by the time of the Closing,
except where the failure of such representations and warranties to be true and
correct and/or the failure to perform, comply with and satisfy such covenants,
agreements and conditions would not constitute a VANTAS Transaction Value
Impairment (other than those contained in Sections 2.4(b) and 2.4(c), which
shall be true and correct). CarrAmerica shall have delivered to VANTAS a
certificate dated the Closing Date and signed by an officer of CarrAmerica
confirming the foregoing.

     (b) CarrAmerica shall have delivered the stock certificates representing
the Shares duly endorsed for transfer and the Notes pursuant to Section 1.2.

     (c) The HQ Merger shall have been consummated immediately prior to the
Closing hereunder.

     (d) CarrAmerica shall have executed and delivered the Assumption Agreement,
in form and substance reasonably satisfactory to the parties hereto and
otherwise satisfying the requirements of Section 5.3.

     Section 6.4 Frustration of Closing Conditions. None of CarrAmerica or
VANTAS may rely on the failure of any condition set forth in Section 6.1,
Section 6.2 or Section 6.3, respectively, to be satisfied if such failure was
caused by such party's failure to perform its obligations hereunder or to use
its commercially reasonable efforts to cause the Closing to occur as required
by Section 5.1.

                                  ARTICLE VII

                              Further Assurances

     From time to time, as and when requested by another party hereto, a party
hereto shall execute and deliver, or cause to be executed and delivered, all
such documents and instruments and shall take, or cause to be taken, all such
further or other actions as such other party may reasonably deem necessary or
desirable to consummate the transactions contemplated by this Agreement.

                                 ARTICLE VIII

                                  Assignment

     This Agreement and the rights and obligations hereunder shall not be
assignable or transferable by (i) the Seller without the prior written consent
of VANTAS or (ii) by VANTAS without the prior written consent of Seller;
provided, that such assignment shall not limit or affect VANTAS's obligations
hereunder; and provided, further, that the Seller may assign its rights and
obligations hereunder in connection with a merger, consolidation or other
similar business combination involving Seller or a sale of all or
substantially all of Seller's assets. Any attempted assignment in violation of
this Section 8 shall be void ab initio and of no further force and effect.

                                  ARTICLE IX

                         No Third-Party Beneficiaries

     This Agreement is for the sole benefit of each of the parties hereto and
their successors and permitted assigns, and nothing herein expressed or
implied shall give or be construed to give to any person, other than the
parties hereto and such successors and assigns, any legal or equitable rights
hereunder.

                                   ARTICLE X

                                  Termination

     (a) Anything contained herein to the contrary notwithstanding this
Agreement shall terminate automatically upon the termination of the Merger
Agreement or the Stock Purchase Agreement in accordance with its terms. In
addition, anything contained herein to the contrary notwithstanding this
Agreement may be terminated and the transactions contemplated hereby abandoned
at any time prior to the Closing:

          (i) by mutual written consent of CarrAmerica and VANTAS;

          (ii) by CarrAmerica if the Company has the right to terminate the
     Merger Agreement in accordance with its terms;

          (iii) by RSI if VANTAS has the right to terminate the Merger
     Agreement in accordance with its terms;

          (iv) by CarrAmerica or Buyer (provided, however, in the case of Buyer,
     only if Buyer has given CarrAmerica at least five business days' prior
     written notice of its intention to terminate pursuant to this Section
     12(a)(iv), which notice may not be given prior to May 1, 2000), if the
     Closing does not occur on or prior to April 30, 2000;

          (v) by CarrAmerica or the Buyer at any time prior to the Closing if
     any Governmental Entity shall have issued a judgment, order or decree or
     taken any other action permanently enjoining, restraining or otherwise
     prohibiting the purchase of the Shares or Notes or any of the other
     material transactions contemplated by this Agreement, and such judgment,
     order or decree or other action shall have become final and
<PAGE>

     nonappealable;

          (vi)by CarrAmerica upon a breach of any representation, warranty or
     covenant on the part of the Buyer set forth in this Agreement, or if any
     representation or warranty shall become untrue, and such breach or
     subsequent failure to remain true constitutes a Company Transaction Value
     Impairment with the result that, in either such case, the conditions set
     forth in Section 6.2 shall have become incapable of being satisfied by
     April 30, 2000 (or otherwise extended); or

          (vii) by the Buyer upon a breach of any representation, warranty or
     covenant of the Companies or CarrAmerica set forth in this Agreement, of if
     any representation or warranty of CarrAmerica shall become untrue, and such
     breach or subsequent failure to remain true constitutes a VANTAS
     Transaction Value Impairment with the result that, in either such case, the
     conditions set forth in Section 6.3 shall have become incapable of being
     satisfied by April 30, 2000 (or as otherwise extended).

     (b) In the event of termination by CarrAmerica or VANTAS pursuant to this
Article X, written notice thereof setting forth the reasons therefore shall
forthwith be given to the other party and VANTAS, and the transactions
contemplated by this Agreement shall be terminated, without further action by
any party.

     (c) If this Agreement is terminated and the transactions contemplated
hereby are abandoned as described in this Article X, this Agreement shall become
void ab initio and of no further force or effect, except for the provisions of
(i) Section 5(b) relating to publicity and (ii) this Article X. Nothing in this
Article X shall be deemed to release any party from any liability for any breach
by such party of the terms and provisions of this Agreement, the Stock Purchase
Agreement or the Merger Agreement.

                                   ARTICLE XI

                              Intentionally Omitted

                                   ARTICLE XII

                                   Amendments

     No amendment, modification or waiver in respect of this Agreement shall be
effective unless it shall be in writing and signed by the party against whom
such amendment, modification or waiver is asserted.

                                  ARTICLE XIII

                                     Notices

     All notices or other communications required or permitted to be given
hereunder shall be in writing and shall be delivered by hand or sent by prepaid
telex, cable or telecopy or sent, postage prepaid, by registered, certified or
express mail or reputable overnight courier service and shall be deemed given
when so delivered by hand, telexed, cabled or telecopied, or if mailed, three
days after mailing (one business day in the case of express mail or overnight
courier service), as follows:

            (i)      if to the Seller,

                     CarrAmerica Realty Corporation
                     1850 K Street, NW
                     Washington, D.C.  20006
                     Telecopy No: 202-729-1160
                     Attention: Linda Madrid, General Counsel

                     with a copy to:

                     Hogan & Hartson, L.L.P.
                     Columbia Square
                     555 Thirteenth Street, N.W.
                     Washington, D.C. 20004-1109
                     Telecopy No:     (202) 637-5910
                     Attention:       J. Warren Gorrell, Jr.
                                      David W. Bonser; and

            (ii)     if to the Companies:

                     OmniUK
                     5 Park Place
                     London, England SW1A 1LP
                     Attention:       Peter Kershaw

                     LuxCo
                     7 Val Sainte Croix
                     L-2015 Luxembourg
                     Attention:       Helene Muller

                     with copies to:

                     HQ Global Workplaces, Inc.
                     15950 N. Dallas Parkway, Suite 350
                     Dallas, Texas 75248
                     Telecopy: (972) 361-8216
                     Attention: Jill Louis, General Counsel

                     and
<PAGE>

                     Hogan & Hartson, L.L.P.
                     Columbia Square
                     555 Thirteenth Street, N.W.
                     Washington, D.C. 20004-1109
                     Telecopy No:     (202) 637-5910
                     Attention:       J. Warren Gorrell, Jr.
                                      David W. Bonser; and

            (iii)    if to VANTAS

                     c/o Reckson Service Industries, Inc.
                     10 East 50th Street
                     Suite 2700
                     New York, NY 10022
                     Telecopy No: (212) 931-8001
                     Attention:   Scott H. Rechler
                                  Jason M. Barnett

                     with copies to:

                     Brown & Wood LLP
                     One World Trade Center
                     New York, NY 10048
                     Telecopy No:     (212) 839-5599
                     Attention:       Joseph W. Armbrust, Jr.
                                      J. Gerard Cummins

or such other address as any party may from time to time specify by written
notice to the other parties hereto.

                                  ARTICLE XIV

                    Interpretation; Exhibits and Schedules

     The headings contained in this Agreement and in any Exhibit to this
Agreement are for reference purposes only and shall not affect in any way the
meaning or interpretation of this Agreement. All Exhibits and Schedules annexed
hereto or referred to herein are hereby incorporated in and made a part of this
Agreement as if set forth in full herein. Any capitalized terms used in any
Schedule or Exhibit but not otherwise defined therein, shall have the meaning as
defined in this Agreement. This Agreement is gender neutral. Any word in this
Agreement that refers to a particular gender shall also refer to all other
genders, including masculine, feminine and neuter.

                                  ARTICLE XV

                                 Counterparts

     This Agreement may be executed in one or more counterparts, all of which
shall be considered one and the same agreement, and shall become effective when
one or more such counterparts have been signed by each of the parties and
delivered to the other parties.

                                  ARTICLE XVI

                               Litigation Costs

     If any litigation with respect to the obligations of the parties under this
Agreement results in a final nonappealable order of a court of competent
jurisdiction that results in a final disposition of such litigation, the
prevailing party, as determined by the court ordering such disposition, shall be
entitled to reasonable attorneys' fees as shall be determined by such court.
Contingent or other percentage compensation arrangements shall not be considered
reasonable attorneys' fees.

                                 ARTICLE XVII

                               Entire Agreement

     This Agreement contains the entire agreement and understanding between the
parties hereto with respect to the subject matter hereof and supersedes all
prior agreements and understandings relating to such subject matter. The parties
hereto shall not be liable or bound to any other party in any manner by any
representations, warranties or covenants relating to such subject matter except
as specifically set forth herein.

                                 ARTICLE XVIII

                             Intentionally Omitted

                                  ARTICLE XIX

                                 Severability

     If any provision of this Agreement (or any portion thereof) or the
application of any such provision (or any portion thereof) to any person or
circumstance shall be held invalid, illegal or unenforceable in any respect by a
court of competent jurisdiction, such invalidity, illegality or unenforceability
shall not affect any other provision hereof (or the remaining portion thereof)
or the application of such provision to any other persons or circumstances.

                                  ARTICLE XX
<PAGE>

                            Consent to Jurisdiction

     The Buyer and RSI, on the one hand, and the Companies and CarrAmerica, on
the other hand, agree to commence any action, suit or proceeding arising out of
this Agreement or the transactions contemplated hereby against the other party
either in a federal court located in the State of Delaware or if such suit,
action or other proceeding may not be brought in such court for jurisdictional
reasons, in a Delaware state court. Each party to this Agreement submits and
consents to personal jurisdiction in any such litigation. The Buyer and RSI, on
the one hand, and the Companies and CarrAmerica, on the other hand, further
agree that service of any process, summons, notice or document delivered by U.S.
registered mail to such party's respective address set forth above shall be
effective service of process for any action, suit or proceeding in Delaware with
respect to any matters to which it has submitted to jurisdiction in this Article
XX. The Buyer, on the one hand, and the Companies, on the other hand,
irrevocably and unconditionally waive any objection to the laying of venue of
any action, suit or proceeding arising out of this Agreement or the transactions
contemplated hereby in (i) any Delaware state court or (ii) any federal court
located in the State of Delaware, and hereby further irrevocably and
unconditionally waives and agrees not to plead or claim in any such court that
any such action, suit or proceeding brought in any such court has been brought
in an inconvenient forum. EACH OF THE PARTIES HERETO IRREVOCABLY WAIVES TRIAL BY
JURY IN ANY ACTION OR PROCEEDING WITH RESPECT TO THIS AGREEMENT.

                                  ARTICLE XXI

                                 Governing Law

     This Agreement shall be governed by and construed in accordance with the
internal laws of the State of Delaware applicable to agreements made and to be
performed entirely within such State, without regard to the conflicts of law
principles of such State.

                                 ARTICLE XXII

                             Disclosure Schedules

     Any fact, circumstance, condition, document or other matter disclosed in
any Schedule referenced herein shall be deemed to have been disclosed for all
purposes under the Agreement including all other relevant Schedules, provided
that the relevance of the disclosure to such other Schedules can be reasonably
discerned from the applicable Schedule.

                                 ARTICLE XXIII

                               Exclusive Remedy

     The parties hereto acknowledge and agree that after the Closing, the terms
of the Indemnification Escrow Agreement shall be the sole remedy for any breach
of any of the representations and warranties contained herein (other than
breaches arising out of fraud) and in no event shall VANTAS or RSI have any
claim against OmniUK or LuxCo with respect to any such breach.
<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed as of the date first written above.

                                     CARRAMERICA REALTY CORPORATION

                                     By:  /s/ Karen B. Dorigan
                                        _________________________________
                                          Name:  Karen B. Dorigan
                                          Title:  Managing Director

                                     RECKSON SERVICES INDUSTRIES, INC.,
                                     solely for the purposes of Section 5.4

                                     By:  /s/ Jason Barnett
                                        ____________________________
                                           Name:  Jason Barnett
                                           Title:  E.V.P.

                                     VANTAS INCORPORATED

                                     By:  /s/ Stephen M. Rathkopf
                                        ____________________________
                                           Name:  Stephen M. Rathkopf
                                           Title:  Secretary

                                     OmniOffices (UK) Limited (solely for
                                           purposes of Article II, Article IV
                                           and Article V)

                                     By:  /s/ Thomas A. Carr
                                           ____________________________
                                           Name:       Thomas A. Carr
                                           Title:      Director

                                     OmniOffices (Lux) 1929 Holding Company
                                        S.A.  (solely for purposes of
                                        Article II, Article IV and Article V)

                                     By:  /s/ Thomas A. Carr
                                           ____________________________
                                           Name:       Thomas A. Carr
                                           Title:      Director

                                     By:  /s/ Gary Kusin
                                          ____________________________
                                           Name:       Gary Kusin
                                           Title:      Director
<PAGE>

                                   Exhibit A

OmniOffices (UK) Limited                                2,006,066 Class B Shares

OmniOffices (Lux) 1929 Holding Company S.A.             144 Class B Shares
<PAGE>

                                  [Exhibit B]

                                [List of Notes]<PAGE>

                                                                    EXHIBIT E

                     INDEMNIFICATION AND ESCROW AGREEMENT

          THIS INDEMNIFICATION AND ESCROW AGREEMENT (this "Agreement") is
entered into as of the ____ day of ____________, 2000 by and among Reckson
Service Industries, Inc., a Delaware corporation ("RSI"), CarrAmerica Realty
Corporation, a Maryland corporation ("CarrAmerica") and [other shareholders to
be added per CarrAmerica's instructions, collectively, the "Shareholders" and
individually a "Shareholder")] and ____________________, a __________
corporation, as escrow agent (the "Escrow Agent") hereunder.

                             W I T N E S S E T H:
                             - - - - - - - - - -

          WHEREAS, RSI, CarrAmerica, VANTAS Incorporated, a Nevada corporation
("VANTAS"), and HQ Global Workplaces, Inc., a Delaware corporation ("HQGW"),
have entered into an Agreement and Plan of Merger dated as of January __, 2000
(the "Merger Agreement") pursuant to which VANTAS will merge with and into
HQGW ("the Merger");

          WHEREAS, on the date hereof, pursuant to an agreement among
[the/certain] Shareholders and RSI dated as of January __, 2000 (the "Stock
Purchase Agreement"), [certain/each] of the Shareholders are selling to RSI,
and RSI is purchasing from such Shareholders, that number of the shares of
voting common stock, par value $.01 per share (the "Voting Common Stock"), and
non-voting common stock, par value $.01 per share (the "Non-Voting Common
Stock" and together with the Voting Common Stock, collectively, the "Shares"),
of HQGW as set forth in, and subject to the terms and conditions of, the Stock
Purchase Agreement for $____ per share in cash for an aggregate purchase price
of $______ (the "Share Consideration");

          WHEREAS, on the date hereof, pursuant to the Merger Agreement, each
issued and outstanding share of (A) Common Stock, par value $.01 per share
("VANTAS Common Stock"), of VANTAS shall be converted into the right to
receive $_____ per share in cash and (B) (i) Series A Convertible Preferred
Stock, par value $ ___ per share, of VANTAS (the "Series A Stock"), (ii)
Series B Convertible Preferred Stock, par value
<PAGE>

$____ per share, of VANTAS (the "Series B Stock"), (iii) Series C Convertible
Preferred Stock, par value $ _______ per share, of VANTAS (the "Series C
Stock"), (iv) Series D Convertible Preferred Stock, par value $ _______ per
share, of VANTAS (the "Series D Stock"), and (v) Series E Convertible Preferred
Stock, par value $____ per share of VANTAS (the "Series E Stock"), other than
shares of Series A Stock, Series B Stock, Series C Stock, Series D Stock and
Series E Stock held in the treasury of VANTAS, are, by virtue of the Merger and
without any action on the part of the holder thereof, being converted into the
right to receive ______ shares of Voting Common Stock ("VANTAS' Share
Consideration");

          WHEREAS, as a condition to the consummation by VANTAS and/or RSI, as
applicable, of the transactions contemplated by the Merger Agreement, the
Stock Purchase Agreement and that certain agreement by and between VANTAS and
CarrAmerica with respect to the purchase and sale of all of the outstanding
capital stock of Omni Offices (UK) Limited ("HQ UK") and Omni Offices (Lux)
1929 Holding Company, S.A. ("HQ LuxCo") (the "UK Agreement"), the Shareholders
hereby have agreed to indemnify and hold harmless RSI from and against certain
losses from certain matters upon the terms and conditions provided herein;

          WHEREAS, as a condition to the consummation by HQGW and the
applicable Shareholders of the transactions contemplated by the Merger
Agreement, the Stock Purchase Agreement and the UK Agreement, RSI has agreed
to indemnify and hold harmless the Shareholders from and against certain
losses from certain matters upon the terms and conditions provided herein;

          WHEREAS, in connection with the Shareholders' indemnification
obligations, the parties have agreed that the Shareholders are depositing an
aggregate of ___ shares of Voting Common Stock and ____ shares of Non-Voting
Common Stock (collectively, the "Shareholder Indemnification Shares") and/or
certain cash (the "Shareholder Cash Collateral") with the Escrow Agent to be
held and disbursed by the Escrow Agent in accordance with this Agreement;

          WHEREAS, in connection with RSI's indemnification obligations, the
parties have agreed that RSI is depositing an aggregate of ____ shares of
Voting Common Stock (the "RSI Indemnification Shares", and together with the
Shareholder Indemnification Shares, the "Indemnification Shares") with the
Escrow Agent to be held and disbursed by the Escrow Agent in accordance with
this Agreement;

          WHEREAS, capitalized words and phrases used and not defined herein
shall have the meanings ascribed to them in the Merger Agreement; and

          WHEREAS, the Escrow Agent is willing to establish and administer
this escrow on the terms set forth in this Agreement.

          NOW, THEREFORE, in consideration of the premises, and other good and
valuable consideration the receipt and sufficiency of which are hereby
acknowledged, the parties hereto do hereby agree as follows:

          1. Certain Definitions. As used in this Agreement, certain
capitalized terms not otherwise defined herein shall have
the following respective meanings:

          "Cash Collateral" shall mean the Shareholder Cash Collateral and any
cash deposited by RSI or any Shareholder in its Escrow Account in substitution
of RSI Indemnification Shares or Shareholder Indemnification Shares in
accordance with Section 2(b).

          "Company Level Loss" shall mean any loss, liability, claim, damage
or expense (including reasonable legal fees and expenses) directly or
indirectly incurred by HQGW or its Subsidiaries and VANTAS or its Subsidiaries
respectively; it being understood that a Company Level Loss shall not include
any consequential, incidental or punitive damages or any Direct Loss.

          "Loss" or "Losses" shall mean a Company Level Loss or a Direct Loss.

          "Direct Loss" shall mean any loss, liability, claim, damage or
expense (including reasonable legal fees and expenses) incurred by (i) any
Shareholder Indemnitee arising from, relating to or as a result of the
inaccuracy at the time made or deemed made of any of the representations or
warranties set forth in: (a) Section 5(B) of the Merger Agreement; and (b)
Section 5 of the Stock Purchase Agreement; or (ii) RSI Indemnitees arising
from, relating to, or as a result of the inaccuracy at the time made or deemed
made of any of the representations or warranties set forth in: (a) Section
4(B) of the Merger Agreement; (b) Section 4 of the Stock Purchase Agreement
and (c) Article II, Section (B) of the UK Agreement; it being understood that
a Direct Loss shall not include (x) any consequential, incidental or punitive
damages, (y) any loss or damages suffered by such party as a result of the
diminution in value (either directly or indirectly) of the interest held by
such party in the Surviving Corporation, or (z) any Company Level Loss.

          "Market Value" shall mean $_____ per share [the price of a share of
Common Stock under the Stock Purchase Agreement].

          "Ownership Percentage" shall mean, with respect to a Shareholder,
the percentage set forth opposite such Shareholder's name on Schedule A
attached hereto [calculated as a fraction, the numerator of which is the
number of shares of all classes of capital stock of HQGW held by such person
immediately prior to the Effective Time, and the denominator of which is the
total number of shares of all classes of capital stock of HQGW held by all
Shareholders who are parties to this Agreement immediately prior to the
Effective Time].
<PAGE>

          "RSI Indemnitees" shall mean RSI and its directors, officers,
employees, shareholders, agents and representatives.

          "RSI's Indemnification Share" shall mean one (1) minus the
Shareholder's Indemnification Share.

          "Shareholder Indemnitees" shall mean each Shareholder and its
directors, officers, employees, shareholders, agents and representatives.

          "Shareholder Litigation" shall mean the legal proceedings disclosed
in Schedule 4(p) of the Merger Agreement under the caption "Omni Offices, Inc.
and CarrAmerica Realty Corporation v. Joseph Kaidanow and Robert Arcoro" and
any and all other future claims, counterclaims, causes of actions or other
proceedings threatened or initiated by or on behalf of Robert Arcoro
("Arcoro") or Joseph Kaidanow ("Kaidanow") that relate to facts or
circumstances or alleged facts or alleged circumstances arising on or prior to
the Closing Date, other than any such claims, causes of action or other
proceedings with respect to and only to the extent of allegations thereon that
any information supplied in writing by RSI to CarrAmerica for inclusion in
materials that HQGW delivers to Arcoro or Kaidanow in connection with the
Merger contains any untrue statement of a material fact with respect to RSI or
VANTAS or omits to state a material fact necessary in order to make the
statements therein with respect to RSI or VANTAS not misleading.

                  "Shareholders' Indemnification Share" shall mean the
aggregate percentage ownership interest of the Voting Common Stock and
Non-Voting Common Stock of Holdco owned by the Shareholders immediately after
the Closing.

          2. Establishment of Escrow Account.

          (a) Each Shareholder and RSI are contemporaneously with the
execution and delivery of this Agreement by each of the parties delivering the
number of Indemnification Shares and/or the amount of Cash Collateral set
forth opposite its name on Schedule A hereto to the Escrow Agent for deposit
into separate escrow accounts (each, an "Escrow Account" and collectively, the
"Escrow Accounts") by the Escrow Agent and the Escrow Agent hereby
acknowledges receipt of the same. All Indemnification Shares and Cash
Collateral in the Escrow Accounts shall be available for distribution by the
Escrow Agent, subject to the provisions of this Agreement, to reimburse any
RSI Indemnitee or any Shareholder Indemnitee, as the case may be, in respect
of any Losses that are indemnifiable pursuant to this Agreement.
Notwithstanding the escrow of the Indemnification Shares, dividends and other
distributions declared and paid on Indemnification Shares held in escrow shall
continue to be paid by HQGW to the respective Shareholders and RSI, all voting
rights with respect to such shares shall inure to the benefit of and be
enjoyed by the respective Shareholders and RSI, and such Shareholders and RSI
shall be the legal and beneficial owners of such shares for all purposes
subject to the terms of this Agreement; provided, that the parties agree that
(i) the Surviving Corporation shall deposit with the Escrow Agent any
securities issued to the Shareholders or RSI in respect of any Indemnification
Shares held in escrow as a result of a stock split or combination of shares of
Voting Common Stock or Non-Voting Common Stock, as the case may be, payment of
a stock dividend or other stock distribution made without receipt of
consideration therefor in or on the Voting Common Stock or Non-Voting Common
Stock, as the case may be, or change of shares of the Voting Common Stock or
Non-Voting Common Stock, as the case may be, into any other securities
pursuant to or as part of a business combination or otherwise, and (ii) such
securities shall be held by the Escrow Agent as, and shall be included within
the definition of, Indemnification Shares, as the case may be; provided,
however, notwithstanding the foregoing proviso, to the extent that any such
distribution of securities is properly taxable as a dividend for federal
income tax purposes, HQGW shall distribute such securities to the respective
Shareholders and RSI. The Escrow Agent agrees that it shall invest any Cash
Collateral in an interest-bearing money market account. The Escrow Agent shall
not have any liability for any loss sustained as a result of any investment
made pursuant to the preceding sentence or as a result of any liquidation of
any such investment prior to its maturity. Any interest earned on any Cash
Collateral shall not be used to increase the amount of the Escrow Account of
any party hereto and shall be paid to the applicable depositor of the Escrow
Account from time to time upon demand, to the extent possible.

          (b) At any time and from time to time after the Closing Date, any or
all of the Indemnification Shares deposited by any Shareholder or RSI in its
Escrow Account on the Closing Date may be withdrawn upon at least five (5)
business days' prior notice by RSI or the Shareholders, as applicable, to the
other, but if and only if simultaneously with such withdrawal the withdrawing
party delivers immediately available funds to the Escrow Agent for deposit
into such party's Escrow Account in an amount equal to the aggregate Market
Value of the number of Indemnification Shares so withdrawn.

          3. Tax Indemnification.

          (a) Tax Indemnification by Shareholders. Subject to the limitations
of indemnification pursuant to Section 5, the Shareholders severally, based on
each such Shareholder's Ownership Percentage, shall indemnify the RSI
Indemnitees against and hold them harmless from (i) any Loss incurred by
reason of any liability of HQGW and its Subsidiaries for Taxes for any
Pre-Closing Tax Period, (ii) any Loss incurred by reason of any liability for
Taxes of the Shareholders or any other person (other than HQGW) which is or
has ever been affiliated with HQGW and its Subsidiaries, and (iii) any Loss
incurred by reason of any liability for reasonable legal, accounting,
<PAGE>

appraisal, consulting or similar fees and expenses for any item attributable
to any item in clause (i) or (ii) above.

          (b) Tax Indemnification by RSI. Subject to the limitations of
indemnification pursuant to Section 5, RSI shall indemnify the Shareholder
Indemnitees against and hold them harmless from (i) any Loss incurred by
reason of any liability of VANTAS and its Subsidiaries for Taxes for any
Pre-Closing Tax Period, (ii) any Loss incurred by reason of any liability for
Taxes of RSI or any other person (other than VANTAS and its Subsidiaries)
which has ever been affiliated with RSI and its Subsidiaries, and (iii) any
Loss incurred by reason of any liability for reasonable legal, accounting,
appraisal, consulting or similar fees and expenses for any item attributable
to any item in clause (i) or (ii) above.

          (c) Straddle Period. For purposes of subparagraphs (a) and (b)
above, in the case of any taxable period that includes (but does not end on)
the Closing Date (a "Straddle Period"):

          (i) real, personal and intangible property Taxes ("Property Taxes")
     of HQGW and its Subsidiaries and VANTAS and its Subsidiaries,
     respectively, for any Pre-Closing Tax Period (other than Taxes imposed in
     connection with the Merger or otherwise in connection with this Agreement
     or the transactions contemplated hereby) shall be equal to the amount of
     such Property Taxes of HQGW and its Subsidiaries and VANTAS and its
     Subsidiaries, respectively, for the entire Straddle Period (limited,
     however, to those Taxes attributable to the assets of HQGW and its
     Subsidiaries and VANTAS and its Subsidiaries, respectively, owned prior
     to the Closing Date) multiplied by a fraction, the numerator of which is
     the number of days during the Straddle Period that are in the Pre-Closing
     Tax Period and the denominator of which is the number of days in the
     Straddle Period; and

          (ii) the Taxes of HQGW and its Subsidiaries and VANTAS and its
     Subsidiaries, respectively (other than Property Taxes and other than
     Taxes referred to in Section 6(e) of this Agreement, which Taxes will be
     governed by such Section), for the Pre-Closing Tax Period shall be
     computed as if such taxable period ended as of the close of business on
     the Closing Date. The indemnity obligations of the Shareholders in
     respect of Taxes for a Straddle Period shall, subject to the limitations
     on indemnification pursuant to Section 5, equal the excess of (x) such
     Taxes for the Pre-Closing Tax Period over (y) the sum of (i) the amount
     of such Taxes for the Pre-Closing Tax Period paid by the Shareholders or
     any of their affiliates (other than HQGW) at any time and (ii) the amount
     of such Taxes paid by HQGW and its Subsidiaries on or prior to the
     Closing Date (which includes any payments of estimated taxes or similar
     amounts made by HQGW and its Subsidiaries on or prior to the Closing Date
     and any amounts of Taxes for which a reserve has been reflected on the
     Company Balance Sheet, even though the amount reflected for such reserve
     has not yet been paid, based on each such Shareholder's Ownership
     Percentage, to the applicable taxing authority). The Shareholders
     severally, based on each such Shareholder's Ownership Percentage, shall
     initially pay such excess to RSI upon the later of (A) five days prior to
     the date on which the Tax Return (including any Tax Return with respect
     to estimated Taxes) with respect to the liability for such Taxes is
     required to be filed (and if no such Tax Return is required to be filed,
     five days prior to the date satisfaction of the Tax liability is required
     by the relevant taxing authority) or (B) ten days after the receipt from
     RSI of notice that such amount is required to be paid pursuant hereto.
     The payments to be made pursuant to this paragraph by the Shareholders
     with respect to a Straddle Period shall be appropriately adjusted to
     reflect any final determination (which shall include the execution of
     Form 870-AD or any successor form) with respect to Taxes for the Straddle
     Period.

     RSI shall cause the Surviving Company to within 10 days of the
     receipt thereof, pay to each of the Shareholders an amount equal to such
     Shareholder's Ownership Percentage, an amount equal to 100% of any refund
     of any Taxes of HQGW with respect to any Pre-Closing Tax Period received
     by HQGW, any of its Subsidiaries or the Surviving Company at any time
     after the Closing Date (including for this purpose any credit against
     Taxes owed for any taxable period ending after the Closing Date, if such
     credit is attributable to a taxable period ending on or prior to the
     Closing Date, any refund of estimated tax payments made on or prior to
     the Closing Date or any application of such payments to either a taxable
     period commencing after the Closing Date or a portion of a Straddle
     Period that is subsequent to the Closing Date, and any interest received
     by HQGW, any of its Subsidiaries or the Surviving Company with respect to
     any of the foregoing from the applicable taxing authority) unless (and
     only to the extent) that the amount of such refund for Taxes was
     reflected as an asset on the Company Balance Sheet.

          4. Other Indemnification.

          (a) Other Indemnification by the Shareholders. (W) The Shareholders
severally, based on each such Shareholder's respective Ownership Percentage,
shall indemnify the RSI Indemnitees against and hold them harmless from any
Company Level Loss (other than any relating to Taxes, for which
indemnification provisions are set forth in Section 3(a), and any relating to
Shareholder Litigation, for which indemnification provisions are set forth in
Section 4)(a)(X)) arising from, relating to or otherwise in respect of any
inaccuracy of any representation or warranty of HQGW contained in the Merger
Agreement (other than the representations set forth in Sections 4(A)(b) and
<PAGE>

4(A)(ee) of the Merger Agreement, for which indemnification provisions are set
forth in Section 4(a)(X) below) or in any certificate delivered pursuant
thereto at the time made or deemed made (regardless of whether or not VANTAS
or RSI was aware of such failure on or prior to the Effective Time).

          (X) All Shareholders severally, based on each such Shareholder's
respective Ownership Percentage, shall indemnify the RSI Indemnitees against
and hold them harmless from any claims, causes of action or other proceedings
arising from, relating to, or otherwise in respect of (i) the failure to
obtain any consent required from the Mercury Executive Offices L.P. (unless as
a result of a breach by RSI of Section 5.4 of the UK Agreement) in connection
with the transactions contemplated by the Merger Agreement or the UK Agreement
(unless VANTAS or RSI fails to perform its obligations under Section 5.4 of
the UK Agreement) or (ii) any inaccuracy of the representations set forth in
Sections 4(A)(b) and 4(A)(ee) of the Merger Agreement. CarrAmerica shall
indemnify the RSI Indemnitees against and hold them harmless from any claims,
causes of action or other proceedings arising from, relating to, or otherwise
in respect of the Shareholder Litigation.

          (Y) Each Shareholder severally with respect to any Direct Loss
attributable to itself only shall indemnify the RSI Indemnitees against and
hold them harmless from any such Direct Loss directly or indirectly suffered
or incurred by any such RSI Indemnitee.

          (Z) CarrAmerica shall indemnify the RSI Indemnitees against and hold
them harmless from any Company Level Loss directly or indirectly suffered or
incurred by any such RSI Indemnitee arising from, relating to or otherwise in
respect of any inaccuracy of the representations and warranties of HQ UK and
HQ LuxCo contained in the UK Agreement or in any certificate delivered
pursuant thereto at the time made or deemed made (regardless of whether or not
VANTAS or RSI was aware of such failure on or prior to the Closing Date).

          (b) Other Indemnification by RSI. (Y) RSI shall indemnify the
Shareholder Indemnitees against and hold them harmless from any Company Level
Loss or Direct Loss (other than any relating to Taxes, for which
indemnification provisions are set forth in Section 3(a)) directly or
indirectly suffered or incurred by them arising from, relating to or otherwise
in respect of any inaccuracy of any representation or warranty of RSI or
VANTAS contained in the Merger Agreement (other than the representations set
forth in Section 5(A)(b) of the Merger Agreement, for which indemnification
provisions are set forth in Section 5(b)(Z) below), the UK Agreement or the
Stock Purchase Agreement or in any certificate delivered pursuant to either of
the foregoing at the time made or deemed made (regardless of whether or not
any Shareholders were aware of such failure on or prior to the Effective
Time).

          (Z) RSI shall indemnify the Shareholder Indemnitees against and hold
them harmless from any claims, causes of actions or other proceedings (i)
arising from, relating to, or otherwise in respect of the matter disclosed in
clause (ii) of Schedules 5(r) or 5(u) to the Merger Agreement or any
inaccuracy of the representations set forth in Section 5(A)(b) of the Merger
Agreement or (ii) threatened or initiated by or on behalf of any holder of
VANTAS Common Stock or Preferred Stock that relate to the execution and
delivery of the Merger Agreement or to any of the transactions contemplated
therein.

          5. Limitations on Indemnification. Any claim brought under Section 3
or 4 is subject in each case to the following limitations and restrictions:

          (a) Damages Net of Insurance, etc. The amount of any Company Level
Loss for which indemnification is provided under this Agreement shall be net
of any amounts actually recovered by the Surviving Corporation under insurance
policies with respect to such Company Level Loss (which the Surviving
Corporation shall use commercially reasonable efforts to recover under such
policies) and the amount of any Loss shall be (i) increased to take account of
any net Tax cost incurred by the indemnified party arising from the receipt of
indemnity payments hereunder (grossed up for such increase), and (ii) reduced
to take account of any net Tax benefit realized by the Surviving Company
arising from the incurrence or payment of any such Loss. In computing the
amount of any such Tax cost or Tax benefit, the indemnified party or the
Surviving Company, as the case may be, shall be deemed to recognize all other
items of income, gain, loss, deduction or credit before recognizing any item
arising from the receipt of any indemnity payment hereunder or the incurrence
or payment of any indemnified Loss. Any indemnity payment under this Agreement
shall be treated as an adjustment to the Merger Consideration for tax
purposes, unless a final determination (which shall include the execution of a
Form 870-AD or successor form) with respect to the indemnified party causes
any such payment not to be treated as an adjustment to the Merger
Consideration for United States Federal income tax purposes.

          (b) Minimum Claim Amounts.

          (i) Claims made by the RSI Indemnitees with respect to Losses for
     which indemnification is provided pursuant to Section 3(a), 3(c), 4(a)(W)
     or 4(a)(Z) shall be required to be paid if and only if the aggregate
     amount of all such Losses, but for this Section 5(b)(i), exceed on a
     cumulative basis $_________ [$5,000,000 divided by RSI's Indemnification
     Share] (the "Holder Basket"), in which event the entire amount of such
     Losses shall be recoverable; it being understood that claims with respect
     to Losses or damages arising from claims, causes of action or other
     proceedings for which indemnification is provided pursuant to Section
     4(a)(X) and 4(a)(Y) shall not be subject to the foregoing limitation.
<PAGE>

          (ii) Claims made by the Shareholder Indemnitees with respect to
     Losses for which indemnification is provided pursuant to Section 3(b),
     3(c) or 4(b)(Y) (with respect to claims for Company Level Losses) shall
     be required to be paid if and only if the aggregate amount of all such
     Losses, but for this Section 5(b)(ii), exceed on a cumulative basis
     $_________ [$5,000,000 divided by fraction representing the Shareholders'
     Indemnification Share] (the "RSI Basket"), in which event the entire
     amount of such Losses shall be recoverable; it being understood that
     claims with respect to Direct Losses for which indemnification is
     provided pursuant to Section 4(b)(Y) or Losses, claims, causes of action
     or other proceedings pursuant to Section 4(b)(Z) shall not be subject to
     the foregoing limitation.

          (iii) In determining whether the Shareholder Indemnitees or RSI
     Indemnitees, as the case may be, is or are entitled to indemnification
     under Section 4, the representations and warranties of the Shareholders
     and HQGW, or RSI and VANTAS, as applicable, shall not be deemed qualified
     by any references to material or materiality contained therein and any
     inaccuracies therein shall be determined without regard to whether such
     inaccuracy constitutes a Company Material Adverse Effect or a VANTAS
     Material Adverse Effect; provided, however, in no event will any
     Shareholder Indemnitees or RSI Indemnitees, as the case may be, be
     entitled (A) to recovery for any Loss relating to or arising out of an
     inaccuracy of any representation or warranty of VANTAS, RSI, HQGW or any
     Shareholder, as the case may be, even if such Shareholder Indemnitee or
     RSI Indemnitee, as applicable, would be entitled to indemnification
     pursuant to Section 5(b)(i) or 5(b)(ii), but for this Section 5(b)(iii),
     unless the Loss related thereto exceeds $50,000, (B) to aggregate items
     referred to in clause (A) of this Section 5(b)(iii) for the purpose of
     exceeding the limitation set forth in clause (A) of this Section
     5(b)(iii), or (C) to otherwise submit the items referred to in clause (A)
     of this Section 5(b)(iii) as Losses reimbursable pursuant to this Section
     5.

          (c) Percentage Recovery.

          (i) If cumulative Company Level Losses under Sections 3(a), 3(c),
     4(a)(W) and 4(a)(Z) exceed the Holder Basket, the indemnification amount
     to be paid to the applicable RSI Indemnitees shall be equal to RSI's
     Indemnification Share of the entire amount of Company Level Losses. In
     all events, 100% of the entire amount of Losses under Sections (4)(a)(X)
     and 4(a)(Y) shall be paid to the applicable RSI Indemnitees.

          (ii) If cumulative Company Level Losses under Sections 3(b), 3(c)
     and 4(b)(Y) exceed the RSI Basket, the indemnification amount to be paid
     to the applicable Shareholder Indemnitees shall be equal to the
     Shareholders' Indemnification Share of the entire amount of Company Level
     Losses. In all events, 100% of the entire amount of Losses that
     constitute Direct Losses of any Shareholder Indemnitee shall be paid to
     the applicable Shareholder Indemnitees.

          (d) Other Limitations on Recovery.

          (i) Except as otherwise provided in the immediately following
     sentence, claims made by any RSI Indemnitee against any Shareholder
     pursuant to this Agreement shall be made solely against the Shareholder
     Indemnification Shares or Cash Collateral deposited into the Escrow
     Account by such Shareholder. Claims made by any RSI Indemnitee against
     any Shareholder with respect to Direct Losses shall be made first against
     the Shareholder Indemnification Shares or Cash Collateral deposited into
     the Escrow Account by such Shareholder in accordance with Section 7, but
     only after any and all amounts in respect of Valid Claims with respect to
     the Company Level Losses shall have first been disbursed in accordance
     with Section 7; provided, that if the amount available in such Escrow
     Account (valuing any Indemnification Shares in accordance with Section 7)
     is less than the full amount of the claim, or if the Escrow Accounts have
     been terminated, a claim may be made directly against such Shareholder,
     which shall be personally liable for the remaining amount of the claim.
     Except as set forth in the preceding sentence, no Shareholder shall have
     any personal liability to any RSI Indemnitee in any respect pursuant to
     this Agreement or otherwise.

          (ii) Except as otherwise provided in the immediately following
     sentence, claims made by any Shareholder Indemnitee against RSI pursuant
     to this Agreement shall be made solely against the RSI Indemnification
     Shares or Cash Collateral deposited into the Escrow Account by RSI.
     Claims made by any Shareholder Indemnitee against RSI with respect to
     Direct Losses shall be made first against the RSI Indemnification Shares
     or cash collateral deposited into the Escrow Account by RSI in accordance
     with Section 7, but only after any and all amounts in respect of Valid
     Claims with respect to Company Level Losses shall have first been
     disbursed in accordance with Section 7; provided that if the amount
     available in such Escrow Account (valuing any Indemnification Shares in
     accordance with Section 7) is less than the full amount of the claim, or
     if the Escrow Accounts have been terminated, a claim may be made directly
     against RSI, which shall be personally liable for the remaining amount of
     the claim. Except as set forth in the immediately preceding sentence, RSI
     shall not have any personal liability to any Shareholder Indemnitee in
     any respect pursuant to this Agreement or otherwise.

          (e) Termination of Indemnities. Notwithstanding anything in this
<PAGE>

Agreement to the contrary, the obligations of the Shareholders and RSI to
provide indemnification under this Agreement shall terminate and be
extinguished forever at the close of business on June 30, 2001, except for (i)
claims under Section 3 hereof and claims under Section 4 hereof that relate to
the representations concerning authorization and benefit plan matters set
forth in Sections 4(b), 4(r), 5(b) and 5(k) of the Merger Agreement and
Sections 2.2 and 2.16 of the UK Agreement and the representations set forth in
the Stock Purchase Agreement, which claims may be made until the expiration of
the applicable statute of limitations; provided, however, that the obligations
of the Shareholders and/or RSI to provide indemnification under this Agreement
shall not terminate at such time with respect to any claim that has been
properly asserted by delivering a notice of such claim to the indemnifying
party in accordance with the terms hereof and such claim has not been paid or
otherwise resolved as of the date on which such indemnity obligation would
otherwise terminate pursuant to this Section 5(e). If a claim has been
properly asserted and not paid or resolved as described above, the indemnity
obligations of the Shareholders or RSI, as applicable, shall continue beyond
June 30, 2001, but (i) the indemnity obligation shall continue only with
respect to the claim in question, and only until such claim is paid or
otherwise finally resolved, and (ii) any amounts in the Escrow Account not
reasonably determined by the indemnified party to be needed to cover the
disputed claim shall be released from the Escrow Account to the Shareholders
or RSI, as applicable.

          6. Other Tax Matters

          (a) For any taxable period of HQGW that includes (but does not end
on) the Closing Date, RSI shall, or shall cause the Surviving Company to,
timely prepare and file with the appropriate taxing authorities all Tax
Returns required to be filed; provided, however, that no such Tax Return shall
be filed without the written consent of the Representative, which consent
shall not be unreasonably withheld. The Shareholders shall reimburse RSI (in
accordance with the procedures set forth in Sections 3(a) and 3(c)) for any
amount owed by the Shareholders to RSI pursuant to such Sections (subject to
the limitation set forth in Section 5) with respect to the taxable periods
covered by such Tax Returns. For any taxable period of HQGW that ends on or
before the Closing Date, HQGW shall timely prepare and file with the
appropriate taxing authorities all Tax Returns required to be filed and shall
pay all Taxes due with respect to such Tax Returns; provided, however, that no
such Tax Return shall be filed without the prior written consent of RSI and
the Represntative, which consent shall not be unreasonably withheld. RSI and
the Shareholders agree to cause HQGW to file all Tax Returns for the taxable
period including the Closing Date on the basis that the relevant taxable
period ended as of the close of business on the Closing Date, unless the
relevant taxing authority will not accept a Tax Return filed on that basis.

          (b) The Shareholders shall cause HQGW to, and the Shareholders, RSI
and the Surviving Company shall, reasonably cooperate, and cause their
respective Affiliates, officers, employees, agents, auditors and other
representatives reasonably to cooperate, in preparing and filing all Tax
Returns and in resolving all disputes and audits with respect to all taxable
periods relating to Taxes, including by maintaining and making available to
each other all records necessary in connection with Taxes, provided, however,
in no event shall RSI be required to provide any Tax Return to the
Shareholders and the Shareholders shall not be required to provide to RSI any
Tax Return not actually in their possession. RSI recognizes that the
Shareholders will need access, from time to time, after the Closing Date, to
certain accounting and Tax records and information held by the Surviving
Company to the extent such records and information pertain to events occurring
prior to the Closing Date acting as representative for the Shareholders;
therefore, RSI agrees after the Closing to cause the Surviving Company to
allow the Representative, and its agents and other representatives, at times
and dates mutually acceptable to the parties, reasonable access to such
records from time to time, during normal business hours and at the
Shareholders' expense.

          (c) An amount equal to 100% of the amount or economic benefit of any
refunds, credits or offsets of Taxes of HQGW for any Pre-Closing Tax Period
(including that portion of a Straddle Period ending on the Closing Date) shall
be for the account of the Shareholders. Notwithstanding the foregoing, (i) any
such refunds, credits or offsets of Taxes shall be for the account of the
Surviving Company and RSI to the extent such refunds, credits or offsets of
Taxes are attributable (determined on a marginal basis) to the carryback from
a taxable period beginning after the Closing Date (or the portion of a
Straddle Period that begins on the day after the Closing Date) of items of
loss, deduction or credit, or other tax items, of the Surviving Company (or
any of its Affiliates, including RSI) and (ii) to the extent RSI or the
Surviving Company, depending on which entity made such payment, pays after the
Closing Date any amount with respect to Taxes for any such Pre-Closing Tax
Period, refunds of such Taxes (determined on a first-in, first-out basis)
shall be for the account of RSI or the Surviving Company, depending on which
entity made such payment. The amount or economic benefit of any refunds,
credits or offsets of Taxes of HQGW or the Surviving Company for any taxable
period beginning after the Closing Date shall be for the account of the
Surviving Company and RSI. The amount or economic benefit of any refunds,
credits or offsets of Taxes of HQGW or the Surviving Company for any Straddle
Period shall be equitably apportioned between the Shareholders, on the one
hand, and RSI and the Surviving Company, on the other hand. Each party shall
forward, and shall cause its Affiliates to forward, to the party entitled
pursuant to this Section 6(c) to receive the amount or economic benefit of a
refund, credit or offset to Tax the amount of such refund, or the economic
benefit of such credit or offset to Tax, within 30 days after such refund is
<PAGE>

received or after such credit or offset is allowed or applied against other
Tax liability, as the case may be; provided, however, that any such amounts
payable pursuant to this Section 6(c) shall be net of any Tax cost or Tax
benefit to the party making payment pursuant to this Section 6(c) and its
Affiliates attributable to the receipt of such refund, credit or offset to Tax
and/or the payment of such amounts pursuant to this Section 6(c). RSI and the
Shareholders shall treat any amounts payable pursuant to this Section 6(c) as
an adjustment to the Merger Consideration unless a final determination (which
shall include the execution of a Form 870-AD or successor form) causes any
such payment not to be treated as an adjustment to the Merger Consideration
for United States Federal income Tax purposes.

          (d) The Shareholders shall supply any necessary information to
enable the Surviving Corporation to file any amended consolidated, combined or
unitary Tax Returns for taxable years ending on or prior to the Closing Date
which are required as a result of examination adjustments made by the IRS or
by the applicable state, municipal, provincial, local or foreign taxing
authorities for such taxable years as finally determined; provided, however,
that no such Tax Return shall be filed without the prior written consent of
the Representative and RSI, which consent shall not be unreasonably withheld.

          For those jurisdictions in which separate Tax Returns are filed by
HQGW, any required amended returns resulting from such examination
adjustments, as finally determined, shall be prepared by the Surviving Company
or RSI and furnished to the Representative, for approval at least 30 days
prior to the due date for filing such Tax Returns.

          (e) All transfer, documentary, sales, use, registration and other
such Taxes (including all applicable real estate transfer or gains Taxes and
stock transfer Taxes) and related fees (including any penalties, interest and
additions to Tax) incurred in connection with the Merger or otherwise in
connection with this Agreement and the transactions contemplated hereby that
are attributable to the assets of HQGW and its Subsidiaries shall be paid by
the Shareholders and that are attributable to the assets of VANTAS and its
Subsidiaries shall be paid by RSI. The Representative and RSI shall cooperate
in timely preparing and filing all Tax Returns as may be required to comply
with the provisions of such Tax laws.

          7. Indemnification Procedures

          (a) Notice of a Claim. In order for a party to be entitled to
indemnification pursuant to this Agreement, the indemnified party shall notify
the indemnifying party in writing of any claim that it reasonably believes is
likely to result in a Loss within ten (10) days of the date such party
receives written notice or otherwise becomes aware of the claim, describing in
reasonable detail the claim (including whether such claim is for Direct Losses
or Company Level Losses) and the estimated amount of the claim; provided,
however, that the failure of an indemnified party so to notify the
indemnifying party of the claim shall not relieve the indemnifying party of
its obligations under this Agreement except to the extent the indemnifying
party shall have been actually prejudiced as a result of such failure (except
that the indemnifying party shall not be liable for any expenses incurred
during the period in which the indemnified party failed to give notice). The
indemnified party shall deliver to the indemnifying party copies of all
notices and documents (including court papers) received by the indemnified
party relating the claim along with the notice referred to above. If the
indemnifying party does not object in writing to the availability of the
indemnity under this Agreement within twenty (20) days after receiving such
notice, then the claim set forth in the notice by such party shall be
considered a valid claim under this Agreement (a "Valid Claim"), and such
Valid Claim (to the extent payable after giving effect to the limitations set
forth in Section 5(b)) shall be paid in accordance with Section 7 hereof. If
any indemnifying party objects in writing as to the availability of the
indemnity with respect to such claim within such twenty (20) day period, then
the indemnifying party and the indemnified party shall proceed in good faith
to negotiate a resolution of such dispute and, if not resolved through
negotiations, such dispute shall be resolved by litigation in an appropriate
court of competent jurisdiction.

          (b) Defense of Third Party Claims. If any Valid Claim arises out of or
involves a claim or demand made by any person against the Surviving Corporation
or the indemnified party (a "Third Party Claim"), then the indemnifying party
shall be entitled to participate in the defense thereof and, if it so chooses
and acknowledges its obligation to indemnify the indemnified party therefor, to
assume the defense thereof with counsel selected by the indemnifying party;
provided, that such counsel is not reasonably objected to by the indemnified
party; and provided further, that if either (i) any indemnified party reasonably
concludes that there may be one or more legal defenses available to it that are
different from or in addition to (and are inconsistent with) those available to
the indemnifying party, or that a conflict or potential conflict exists between
any indemnified party, on the one hand, and any indemnifying party, on the other
hand (a "Conflicting Matter"), or (ii) the Third Party Claim seeks an order,
injunction or other equitable relief or relief for other than money damages
which the indemnified party reasonably concludes cannot be separated from any
related claim for money damages (a "Specific Performance Matter"), the
indemnifying party will not have the right to direct the defense of such action
on behalf of such indemnified party with respect to such Conflicting Matter or
Specific Performance Matter, and the indemnified party shall direct the defense
of the portion of such claim that constitutes a Conflicting Matter or Specific
Performance Matter through counsel (including a local counsel, if necessary) of
its choosing, at the expense of the indemnified party. Should the
<PAGE>

indemnifying party so elect to assume the defense of a Third Party Claim, the
indemnifying party shall not be liable to the indemnified party for legal
expenses subsequently incurred by the indemnified party in connection with the
defense thereof. If the indemnifying party assumes such defense, the indemnified
party shall have the right to participate in the defense thereof and to employ
counsel, at its own expense, separate from the counsel employed by the
indemnifying party, it being understood that the indemnifying party shall
control such defense. Notwithstanding the foregoing, the indemnifying party
shall be liable for the fees and expenses of counsel employed by the indemnified
party for any period during which the indemnifying party has failed to assume
the defense thereof (other than during the period prior to the time the
indemnified party shall have given notice of the Third Party Claim as provided
above).

          If the indemnifying party so elects to assume the defense of any Third
Party Claim, the indemnified party shall cooperate with the indemnifying party
in the defense or prosecution thereof. Such cooperation shall include the
retention and (upon the indemnifying party's request) the provision to the
indemnifying party of records and information which are reasonably relevant to
such Third Party Claim, and making employees available on a mutually convenient
basis to provide additional information and explanation of any material provided
hereunder. Whether or not the indemnifying party shall have assumed the defense
of a Third Party Claim, the indemnified party shall not admit any liability with
respect to, or settle, compromise or discharge, such Third Party Claim without
the indemnifying party's prior written consent (which consent shall not be
unreasonably withheld). If the indemnifying party shall have assumed the defense
of a Third Party Claim, the indemnified party shall agree to any settlement,
compromise or discharge of a Third Party Claim which the indemnifying party may
recommend and which by its terms obligates the indemnifying party to pay the
full amount of the liability in connection with such Third Party Claim, which
releases the indemnifying party completely in connection with such Third Party
Claim and which would not otherwise adversely affect the Indemnified Party.

          (c) Procedures Unique to Tax Claims. With respect to any claim made by
any taxing authority (a "Tax Claim") covered by Section 3(a) hereof, the
Representative shall control all proceedings and may make all decisions taken in
connection with such Tax Claim (including selection of counsel) and, without
limiting the foregoing, may in its sole discretion pursue or forego any and all
administrative appeals, proceedings, hearings and conferences with any taxing
authority with respect thereto, and may, in its sole discretion, either pay the
Tax claimed and sue for a refund where applicable law permits such refund suits
or contest the Tax Claim in any permissible manner; provided, however, that the
Representative must first consult in good faith with RSI before taking any
action with respect to the conduct of a Tax Claim. Notwithstanding the
foregoing, (i) the Representative shall not settle any Tax Claim without the
prior written consent of RSI, which consent shall not be unreasonably withheld,
(ii) RSI, and counsel of its own choosing, shall have the right to participate
fully in all aspects of the defense of such Tax Claim, (iii) the Representative
shall inform RSI, reasonably promptly in advance, of the date, time and place of
all administrative and judicial meetings, conferences, hearings and other
proceedings relating to such Tax Claim, (iv) RSI shall be entitled to have its
representatives (including counsel, accountants and consultants) attend and
participate in any such administrative and judicial meetings, conferences,
hearings and other proceedings relating to such Tax Claim and (v) the
Representative shall provide to RSI all information, document requests and
responses, proposed notices of deficiency, notices of deficiency, revenue
agent's reports, protests, petitions and any other documents relating to such
Tax Claim promptly upon receipt from, or in advance of submission to (as the
case may be), the relevant taxing authority.

          With respect to any Tax Claim covered by Section 3(b) hereof, RSI
shall control all proceedings and may make all decisions taken in connection
with such Tax Claim (including selection of counsel) and, without limiting the
foregoing, may in its sole discretion pursue or forego any and all
administrative appeals, proceedings, hearings and conferences with any taxing
authority with respect thereto, and may, in its sole discretion, either pay the
Tax claimed and sue for a refund where applicable law permits such refund suits
or contest the Tax Claim in any permissible manner; provided, however, that RSI
must first consult in good faith with the Representative before taking any
action with respect to the conduct of a Tax Claim. Notwithstanding the
foregoing, (i) RSI shall not settle any Tax Claim without the prior written
consent of the Representative, which consent shall not be unreasonably withheld,
(ii) the Representative, and counsel of its own choosing, shall have the right
to participate fully in all aspects of the defense of such Tax Claim, (iii) RSI
shall inform the Representative, reasonably promptly in advance, of the date,
time and place of all administrative and judicial meetings, conferences,
hearings and other proceedings relating to such Tax Claim, (iv) the
Representative shall be entitled to have its representatives (including counsel,
accountants and consultants) attend and participate in any such administrative
and judicial meetings, conferences, hearings and other proceedings relating to
such Tax Claim and (v) RSI shall provide to the Representative all information,
document requests and responses, proposed notices of deficiency, notices of
deficiency, revenue agent's reports, protests, petitions and any other documents
relating to such Tax Claim promptly upon receipt from, or in advance of
submission to (as the case may be), the relevant taxing authority.

          The Representative and RSI shall jointly control and participate in
all proceedings taken in connection with any Tax Claim relating to Taxes of HQGW
and its Subsidiaries for a Straddle Period. Neither the Representative
<PAGE>

nor RSI shall settle any such Tax Claim without the prior written consent of the
other.

          RSI, on the one hand, and each Shareholder, on the other hand, shall,
reasonably cooperate in contesting any Tax Claim, which cooperation shall
include the retention and, upon request, the provision to the requesting person
of records and information which are reasonably relevant to such Tax Claim, and
making employees available on a mutually convenient basis to provide additional
information or explanation of any material provided hereunder or to testify at
proceedings relating to such Tax Claim.

          8. Escrow Disbursements in Respect of Valid Claims.

          (a) Upon receipt of (i) a written notice signed jointly by a duly
authorized officer of the Representative and a duly authorized officer of RSI or
(ii) a certified copy of a final, non-appealable judgment of a court of
competent jurisdiction specifying the amount of Loss to be paid to RSI or the
Shareholders, as the case may be, the Escrow Agent shall, subject to the terms
of this Agreement, distribute to the RSI Indemnitee or the Shareholder
Indemnitee, as the case may be, from each Shareholder's or RSI's, as the case
may be, Escrow Account, a number of Indemnification Shares (each such share
being deemed to have a value equal to the Market Value) and any Cash Collateral
equal in value to such Shareholders' or RSI's, as the case may be, share of the
total amount of Loss specified in such notice (taking into account the
limitations set forth in Section 5(b) hereof). If there are insufficient
Indemnification Shares (based on the Market Value) and Cash Collateral remaining
in such Shareholder's or RSI's, as the case may be, Escrow Account to satisfy of
the total amount of Loss specified in such notice, the Escrow Agent shall,
subject to the terms of this Agreement, distribute to the RSI Indemnitee or the
Shareholder Indemnitee, as the case may be, all Indemnification Shares and Cash
Collateral held in such Shareholder's or RSI's, as the case may be, Escrow
Account.

          (b) Notwithstanding anything herein to the contrary, to the extent
that Indemnification Shares and/or Cash Collateral are to be distributed to the
RSI Indemnitee or the Shareholder Indemnitee, as the case may be, to pay a Loss,
in the absence of instructions pursuant to the proviso to this sentence (of
which the Escrow Agent shall have no duty or obligation to inquire about) given
through written notice to the Escrow Agent by the Shareholder or RSI with
respect to the Indemnification Shares and Cash Collateral in the relevant Escrow
Account, the Escrow Agent will satisfy the portion of such Loss payable by such
Shareholder or RSI, as the case may be, (i) first, by distributing to the RSI
Indemnitee or the Shareholder Indemnitee, as the case may be, the
Indemnification Shares deposited by such Shareholder or RSI, as the case may be,
in its Escrow Account on the Closing Date, and (ii) second, by distributing any
Cash Collateral in such Shareholder's or RSI's, as the case may be, Escrow
Account; provided, that any Shareholder or RSI, as the case may be, by written
notice to the Escrow Agent, may direct that Cash Collateral referred to in
clause (ii) above be distributed from its Escrow Account prior to the
distribution of Indemnification Shares. This provision shall be controlling at
all times unless such instructions have been received prior to such
distributions.

          9. Final Distribution. At the close of business on June 30, 2001, any
Indemnification Shares and Cash Collateral remaining in an Escrow Account, and
which are not subject to retention pursuant to Section 5(e), shall be returned
by the Escrow Agent to the respective Shareholders or RSI who contributed such
Indemnification Shares or Cash Collateral upon joint notification by the
Representative and RSI.

          10. Rights and Liabilities of Escrow Agent. The acceptance by the
Escrow Agent of its duties under this Agreement is subject to the following
terms and conditions.

          (a) The Escrow Agent shall in no event be liable for any failure of
the conditions of this escrow or any damage caused by the exercise of its
discretion or the performance of its other duties under this Agreement, except
to the extent that such failure or damage arises from its own gross negligence
or willful misconduct.

          (b) The Escrow Agent shall be protected in acting upon any written
notice, instruction, waiver, consent, receipt or other paper or document which
the Escrow Agent in good faith believes to be genuine and what it purports to
be.

          (c) The Escrow Agent is neither party to nor is bound by or charged
with notice of the terms, provisions, legality, validity or sufficiency of the
documents delivered to it other than this Agreement, and it shall not be liable
or responsible for its failure to ascertain the terms or conditions, or to
comply with any of the provisions of any such document.

          (d) If any dispute arises between the parties or with any third person
with respect to this escrow or its terms or conditions, the Escrow Agent shall
not be required to determine the same or take any action in connection therewith
but it may await the settlement of the same in accordance with the provisions of
this Agreement, unless it receives instructions to the contrary signed by both
RSI and the Representative.

          (e) In consideration of ___________________________ acting as Escrow
Agent, RSI and the Shareholders mutually agree to indemnify ___________________
and hold it harmless from and against any and all losses, claims, costs,
liabilities, obligations, damages and expenses
<PAGE>

(including, without limitation, reasonable attorneys' fees) reasonably incurred
by ___________________________ resulting from any commenced or threatened
litigation or administrative proceeding which arises out of or is in any way
based on any action taken or not taken by the Escrow Agent pursuant to this
Agreement; provided, however, that RSI and the Shareholders shall not be
obligated to so indemnify the Escrow Agent for its own gross negligence or
willful misconduct.

          (f) In no event shall the Escrow Agent be liable for special, indirect
or consequential loss or damage of any kind whatsoever (including but not
limited to lost profits), even if the Escrow Agent has been advised of the
likelihood of such loss or damage and regardless of the form of action.

          (g) The Escrow Agent may resign at any time by giving 60 days written
notice thereof to RSI and the Representative at the addresses referred to in
Section 7 below. Upon notice of resignation of the Escrow Agent, the parties
agree to find a replacement escrow agent within 60 days. The Escrow Agent agrees
to deliver the Indemnification Shares and any substitute collateral in the
Escrow Accounts to such replacement escrow agent upon written notification by
both the parties and the replacement escrow agent. In the event a successor is
not found within 60 days, the Escrow Agent may petition any court of competent
jurisdiction for the appointment of a successor escrow agent or for instructions
as to the disposition of the Indemnification Shares and any substitute
collateral in the Escrow Accounts and it shall thereby be released from any and
all responsibility and/or liability to the parties.

          (h) The parties understand and agree that the Escrow Agent cannot give
legal advice as to any conditions or requirements in this escrow. Each party
will seek legal counsel for any legal opinion or advice that each party needs.

          (i) The Escrow Agent may seek the advice of counsel as to any decision
required to be taken hereunder and shall be held harmless for any such actions
taken in accordance with the advice of such counsel.

          (j) All fees and related expenses of the Escrow Agent for its service
hereunder (including fees of its legal counsel) shall be paid equally by RSI and
the Shareholders. Such fees and expenses shall be determined in accordance with
the fee schedule attached hereto as Schedule B or as otherwise provided to RSI
and the Representative.

          11. Fractional Shares. No fractional shares shall be delivered to
satisfy any claims. If the Indemnification Shares to be so delivered from any
Shareholder's or RSI's, as the case may be, Escrow Account would include a
fractional share, the parties hereto agree that the Representative and RSI may
round such fraction to the nearest whole share.

          12. Notices. All notices or other communications required or permitted
to be given hereunder shall be in writing and shall be delivered by hand or sent
by prepaid telex, cable or telecopy or sent, postage prepaid, by registered,
certified or express mail or reputable overnight courier service and shall be
deemed given when so delivered by hand, telexed, cabled or telecopied, or if
mailed, three days after mailing (one business day in the case of express mail
or overnight courier service), as follows:

                           If to the Shareholders:

                           At the address set forth opposite
                           such Shareholder's name on the
                           signature page hereto

                           with a copy to:

                           Hogan & Hartson, L.L.P.,
                           Columbia Square
                           555 Thirteenth Street, N.W.
                           Washington, DC  20004

                           Telecopy No:  (202) 637-5910
                           Attention:   Warren Gorrell
                                        David Bonser; and

                           (ii) if to RSI:

                           Reckson Service Industries, Inc.
                           10 East 50th Street
                           Suite 2700
                           New York, NY  10022

                           Telecopy No:  (212) 931-8001
                           Attention:  Scott H. Rechler

                           with copies to:

                           Brown & Wood LLP
                           One World Trade Center
                           New York, NY  10048
<PAGE>

                           Telecopy No:  (212) 839-5599
                           Attention:      Joseph W. Armbrust, Jr.
                                           J. Gerard Cummins

                           If to the Escrow Agent:

                           [To come]

or such other address as any party may from time to time specify by written
notice to the other parties hereto.

          13. No Assignment or Benefit to Third Parties. This Agreement may
not be assigned by operation of law or otherwise, except by RSI to one or more
entities controlled by RSI (with RSI remaining responsible for its obligations
under this Agreement). Notwithstanding the foregoing, the rights or duties of
each of the parties under this Agreement may be assigned by such party in
connection with a sale of all or substantially all of its assets or a merger,
consolidation or other similar business combination transaction. Nothing
expressed or implied in this Agreement is intended, nor shall be construed, to
confer (a) any rights, remedies, obligations or liabilities, legal or
equitable, other than as provided in this Agreement or (b) otherwise
constitute any person (other than the Representative) a third party
beneficiary under or by reason of this Agreement (it being acknowledged that
the Representative is a third party beneficiary of this Agreement and is
entitled to enforce the relevant provisions of this Agreement).

          14. Headings. The headings of the Sections of this Agreement are for
convenience only and do not constitute a part of this Agreement.

          15. Counterparts. This Agreement may be executed in one or more
counterparts, all of which shall be considered one and the same agreement and
shall become effective when one or more counterparts have been signed by each
party and delivered to the others.

          16. Applicable Law. This Agreement shall be construed and enforced in
accordance with, and governed by the laws of the State of Delaware, without
application of any choice of law provisions that would apply any law other than
the laws of Delaware.

          17. Conflicts. In the event of any conflicts with respect to the
duties and obligations of the Escrow Agent between this Agreement and the Merger
Agreement, the provisions of this Agreement shall be deemed to control.

          18. Several Liability. Anything in this Agreement to the contrary
notwithstanding, the representations, warranties, covenants and agreements of
the Shareholders set forth herein are several and not joint.

          19. Powers of the Representative. Each Shareholder by executing this
Agreement hereby appoints CarrAmerica as such Shareholder's agent and attorney
in fact (the "Representative") hereunder with full irrevocable power and
authority in the place and stead of such Shareholder and in the name of such
Shareholder to take any and all actions, and to execute any and all instruments
and other documents, which in the sole judgment of the Representative are
necessary or appropriate in handling claims for Losses made pursuant to Section
3, 4(a)(W), 4(a)(X) and 4(b) of this Agreement. Said power of attorney shall not
be affected by the subsequent incapacity of any Shareholder. Without limiting
the generality of the foregoing, each of the Shareholders agrees that the
Representative (1) has full power and authority to take such action on behalf of
the Shareholders with respect to any Indemnification Shares and Cash Collateral
held by the Escrow Agent and with respect to any and all claims for Losses
(including, without limitation, any decisions to accept or to challenge any
claims for Losses) as the Representative in its sole discretion may determine
(except to the extent that this Agreement provides for any action with respect
to such Indemnification Shares or Cash Collateral to be taken by the
Shareholders themselves) and (2) shall represent the Shareholders for all
purposes in connection with the claims specified above, including the receipt of
notices and the exercise or wavier of any rights with respect to RSI's
obligations under this Agreement, and resolution of disputes or uncertainties
arising hereunder and thereunder (except to the extent that any such agreement
expressly provides for any action to be taken or other matter to be dealt with
by the Shareholders themselves). The Representative shall forward the
Shareholders copies of all notices of Claims received from any RSI Indemnitee
and of the disposition of all such Claims. The Shareholders also agree that the
Shareholders shall be bound by all decisions of the Representative pursuant to
the authority granted hereunder, and that such authority may not be revoked
during the term of this Agreement.

Except as expressly set forth in this Agreement, it is understood that the
Representative is not assuming any responsibility or liability to any person by
virtue of the powers granted by the Shareholders hereby. The Representative
shall not make any representations with respect to and shall have no
responsibility for the transactions contemplated by the Merger Agreement, the
Stock Purchase Agreement or the U.K. Purchase Agreement or any aspect thereof
except as expressly set forth in such agreements. The Representative shall not
be liable to any other Shareholder for any error of judgment or for any act done
or omitted or for any mistake of fact or law except for such Representative's
own gross negligence or bad faith. Each Shareholder agrees to indemnify the
Representative and to hold the Representative harmless against any loss, claim,
damage or liability incurred
<PAGE>

by him arising out of or in connection with acting as the Representative
pursuant to this Agreement, as well as the cost and expense of investigating and
defending against any such loss, claim, damage or liability, except to the
extent such loss, claim, damage or liability is due to the gross negligence or
bad faith of the Representative. Each Shareholder agrees that the Representative
may consult with counsel of its own choice (who may be counsel for CarrAmerica
or any affiliate thereof) and it shall have full and complete authorization and
protection for any action taken or suffered by it hereunder in good faith and in
accordance with the opinion of such counsel. It is understood that the
Representative may, without breaching any express or implied obligation to any
Shareholder hereunder, release, amend or modify any other power of attorney
granted by any other person under any related agreement.

          20. Litigation Costs. If any litigation with respect to the
obligations of the parties under this Agreement results in a final nonappealable
order of a court of competent jurisdiction that results in a final disposition
of such litigation, the prevailing party, as determined by the court ordering
such disposition, shall be entitled to reasonable attorneys' fees as shall be
determined by such court. contingent or other percentage compensation
arrangements shall not be considered reasonable attorneys' fees.

          21. Consent to Jurisdiction. CarrAmerica, on the one hand, and RSI, on
the other hand, agree to commence any action, suit or proceeding relating hereto
against the other party either in a federal court located in the State of
Delaware or if such suit, action or other proceeding may not be brought in such
court for jurisdictional reasons, in a Delaware state court. Each party to this
Agreement submits and consents to personal jurisdiction in any such litigation.
CarrAmerica, on the one hand, and RSI, on the other hand, further agree that
service of any process, summons, notice or document delivered by U.S. registered
mail to such party's respective address set forth above shall be effective
service of process for any action, suit or proceeding in Delaware with respect
to any matters to which it has submitted to jurisdiction in this Section 21.
CarrAmerica, on the one hand, and RSI, on the other hand, irrevocably and
unconditionally waive any objection to the laying of venue of any action, suit
or proceeding arising out of this Agreement or the transactions contemplated
hereby in (i) any Delaware state court or (ii) any federal court located in the
State of Delaware, and hereby further irrevocably and unconditionally waives and
agrees not to plead or claim in any such court that any such action, suit or
proceeding brought in any such court has been brought in an inconvenient forum.
EACH OF THE PARTIES HERETO IRREVOCABLY WAIVES TRIAL BY JURY IN ANY ACTION OR
PROCEEDING WITH RESPECT TO THIS AGREEMENT.

          22. Amendment. This Agreement may be amended by written agreement
signed by RSI and each Shareholder that would be adversely affected by such
amendment. The parties furthermore agree that the Merger Agreement will not be
amended or otherwise modified to increase the duties or liabilities of the
Escrow Agent without obtaining the prior written consent of the Escrow Agent in
each instance.

          23. Waiver. Any party to this Agreement may extend the time for the
performance of any of the obligations or other acts of any other party hereto,
or waive compliance with any of the agreements of any other party or with any
condition to the obligations hereunder, in each case only to the extent that
such obligations, agreements and conditions are intended for its benefit, each
Shareholder hereby severally agreeing that any such extension or waiver by such
Shareholder may be given by the Representative and each Shareholder hereby
severally confirming that it has appointed the Representative as its
attorney-in-fact to give any such extension or waiver on behalf of such
Shareholder.
<PAGE>

          IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be duly executed as of the date first written above.

                                               CARRAMERICA REALTY CORPORATION

                                               By: __________________________
                                                   Name:
                                                   Title:

                                               RECKSON SERVICE INDUSTRIES, INC.

                                               By: __________________________
                                                   Name:
                                                   Title:

                                               [ESCROW AGENT]

                                               as Escrow Agent

                                               [OTHER ADDITIONAL
                                                STOCKHOLDERS, AS APPLICABLE]
<PAGE>

                                  Schedule A

                       [List of Indemnification Shares]
<PAGE>

                                  Schedule B
                       Reckson Service Industries, Inc.
                               Escrow Agent Fees

ACCEPTANCE FEE                                                             $[ ]
Includes examination of the Escrow Agreement and establishment of the security
safekeeping records.

ADMINISTRATION FEE, per year or portion thereof:                           $[ ]
Includes performance of duties outlined in the escrow agreement. Payable on
receipt of the shares and each year thereafter.

       THIS FEE SCHEDULE IS CONFIDENTIAL AND MAY NOT BE REVEALED TO ANY
             PARTY OUTSIDE THE WORKING GROUP IN THIS TRANSACTION

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