<PAGE>

                                VOTING AGREEMENT

         THIS VOTING AGREEMENT (the "Agreement") is entered into as of March 29,
2001, among CORE, Inc., a Massachusetts corporation (the "COMPANY"), the
undersigned stockholders (each a "STOCKHOLDER" and collectively, the
"STOCKHOLDERS") of the Company, and Fortis, Inc., a Nevada corporation
("PARENT").

         WHEREAS, concurrently with the execution and delivery of this
Agreement, CORE Merger Sub, Inc., a Massachusetts corporation and a wholly owned
subsidiary of Parent ("PURCHASER"), Parent and the Company have entered into an
Agreement and Plan of Merger dated of even date herewith (the "MERGER
AGREEMENT"), providing for the merger of Purchaser with and into the Company
(the "MERGER") pursuant to the terms and conditions of the Merger Agreement, and
setting forth certain representations, warranties, covenants and agreements of
the parties thereto in connection with the Merger; and

         WHEREAS, as an inducement and a condition to Parent entering into the
Merger Agreement, pursuant to which each Stockholder will receive the Merger
Price (as defined in the Merger Agreement) in exchange for each share of Common
Stock, par value $.10 per share, of the Company ("COMPANY COMMON STOCK") owned
by such Stockholder, the Stockholders each have agreed to enter into this
Agreement;

         NOW, THEREFORE, for good and valuable consideration, the receipt,
sufficiency and adequacy of which is hereby acknowledged, the parties hereto
agree as follows:

         1.       REPRESENTATIONS OF STOCKHOLDERS. Each of the Stockholders
severally represents as to himself or herself:

                  (a) That such Stockholder is (i) the beneficial owner (as such
term is defined in the Securities Exchange Act of 1934, as amended (the "1934
ACT")) of the number of shares of Company Common Stock set forth opposite such
Stockholder's name under the heading "Common Shares" on EXHIBIT A hereto
(collectively, such Stockholder's "COMMON SHARES") and (ii) the holder of stock
options to purchase the number of shares of Company Common Stock set forth
opposite such Stockholder's name under the heading "Option Shares" on EXHIBIT A
hereto (collectively, such Stockholder's "OPTION SHARES"). Each Stockholder's
Common Shares and Option Shares are hereinafter collectively referred to as
"SHARES."

                  (b) That such Stockholder does not beneficially own any shares
of Company Common Stock other than his or her Shares.

                  (c) That, except as disclosed on EXHIBIT B hereto, such
Stockholder has the right, power and authority to execute and deliver this
Agreement and to perform his or her obligations under this Agreement, and this
Agreement has been duly executed and delivered by such Stockholder and
constitutes a valid and legally binding agreement of such Stockholder,
enforceable in accordance with its terms, subject to bankruptcy,

<PAGE>

insolvency, fraudulent transfer, reorganization, moratorium and similar laws of
general applicability relating to or affecting creditors' rights and to general
equity principles; and such execution, delivery and performance by Stockholder
of this Agreement will not (i) conflict with, require a consent, waiver or
approval under, or result in a breach of or default under, any of the terms of
any contract, commitment or other obligation (written or oral) to which such
Stockholder is a party or by which such Stockholder is bound; (ii) violate any
order, writ, injunction decree or statute, or any rule or regulation, applicable
to Stockholder or any of the properties or assets of Stockholder; or (iii)
result in the creation of, or impose any obligation on such Stockholder to
create, any lien, charge or other encumbrance of any nature whatsoever upon the
Shares, other than as imposed pursuant to this Agreement.

                  (d) That, except as disclosed on EXHIBIT B hereto or as
permitted pursuant to Section 6, such Stockholder's Common Shares and rights to
his or her Option Shares are held by such Stockholder, or by a nominee or
custodian for the account of such Stockholder, free and clear of all pledges,
liens, proxies, claims, charges, security interests, preemptive rights and any
other encumbrances whatsoever with respect to the ownership, transfer or voting
of such Shares; and there are no outstanding options, warrants or rights to
purchase or acquire, or other agreements relating to, such Shares other than
this Agreement.

                  (e) That such Stockholder understands and acknowledges that
Parent is entering into, and causing Purchaser to enter into, the Merger
Agreement in reliance upon the Stockholder's execution and delivery of this
Agreement. Each Stockholder acknowledges that the irrevocable proxy set forth in
Section 3 is granted in consideration for the execution and delivery of the
Merger Agreement by Parent and Purchaser.

The representations and warranties contained herein shall be made as of the date
hereof and each Stockholder shall (a) use all reasonable efforts to assure that
each representation and warranty remains true and correct and (b) not take any
action that would cause any representation or warranty not to be true and
correct, as of each date from the date hereof through and including the date
that the Merger is consummated or the Merger Agreement is terminated.

         2. AGREEMENT TO VOTE COMMON SHARES. Each of the Stockholders severally
agrees to vote his or her Common Shares and any New Shares (as defined in
Section 7 hereof), and shall cause any holder of record of his or her Common
Shares or New Shares to vote such Common Shares or New Shares, (a) in favor of
adoption and approval of the Merger Agreement and the Merger (and each other
action and transaction contemplated by the Merger Agreement and this Agreement)
at every meeting of the stockholders of the Company at which such matters are
considered and at every adjournment thereof (provided that the terms of the
Merger Agreement shall not have been amended to reduce the Merger Price to less
than $4.92 per share or to impose any specific obligation on the Stockholder
that is not imposed uniformly on all stockholders of the Company, except as such
Stockholder has agreed in writing), and (b) against any action or proposal that
would compete with or reasonably could be expected to serve to interfere
materially with,


                                       -2-
<PAGE>

delay, discourage, adversely affect or inhibit the timely consummation of the
Merger. Any such vote shall be cast or consent shall be given in accordance with
such procedures relating thereto as shall ensure that it is duly counted for
purposes of determining that a quorum is present and for purposes of recording
the results of such vote or consent. Notwithstanding the foregoing, neither (a)
the inability of any Stockholder to vote his or her Common Shares or New Shares
in accordance with this Section 2 due to the presence at any meeting of
stockholders of the proxy granted pursuant to Section 3, (b) the failure of any
Stockholder to attend in person a meeting of the stockholders of the Company or
adjournment thereof or (c) actions taken by any Stockholder in connection with
such Stockholder's appointment as a proxy to represent and vote shares of the
Company's stockholders (other than the Stockholder) at a meeting of stockholders
shall be a violation of this Agreement.

         3.       GRANT OF LIMITED IRREVOCABLE PROXY; APPOINTMENT OF PROXY.

                  (a) Each Stockholder hereby irrevocably grants to and appoints
Jerome A. Atkinson, General Counsel of Parent, Drew Desky, Vice
President--Mergers and Acquisitions of Parent, and Katherine Greenzang, Vice
President and Corporate Counsel of Parent, in their respective capacities as
officers of Parent, and any individual who shall hereafter succeed to any such
office of Parent (individually a "Proxy"), and each of them individually, the
Stockholder's limited proxy and attorney-in-fact (with full power of
substitution), for and in the name, place and stead of the Stockholder, solely
to vote the Stockholder's Common Shares and any New Shares which are held of
record by the Stockholder, or grant a consent or approval in respect of such
Common Shares and New Shares (i) in favor of adoption and approval of the Merger
Agreement and the Merger (and each other action and transaction contemplated by
the Merger Agreement and this Agreement) at every meeting of the stockholders of
the Company at which such matters are considered and at every adjournment
thereof (provided that the terms of the Merger Agreement shall not have been
amended to reduce the Merger Price to less than $4.92 per share or to impose any
specific obligation on the Stockholder that is not imposed uniformly on all
stockholders of the Company, except as such Stockholder has agreed in writing),
and (ii) against any action or proposal that would compete with or serve to
interfere materially with, delay, discourage, adversely affect or inhibit the
timely consummation of the Merger.

                  (b) The proxies granted hereunder shall terminate, with no
further action on the part of any Stockholder, upon the earlier of (i)
termination of the Merger Agreement or (ii) September 30, 2001.

                  (c) Each Proxy severally agrees to vote all Common Shares and
any New Shares in favor of adoption and approval of the Merger Agreement and the
Merger at every meeting of the stockholders of the Company at which such matters
are considered and at every adjournment thereof.

                  (d) Each Stockholder represents that any proxies heretofore
given in respect of such Stockholder's Shares are not irrevocable, and that such
Stockholder shall,


                                       -3-
<PAGE>

simultaneously with the execution of this Agreement, take any and all actions
necessary to revoke such proxies in accordance with their terms.

                  (e) Each Stockholder hereby affirms that the irrevocable proxy
set forth in this Section 3 is given in connection with the execution of the
Merger Agreement, and that such irrevocable proxy is given to secure the
performance of the duties of the Stockholder under this Agreement. Each
Stockholder hereby further affirms that this proxy is irrevocable to the extent
permitted by Massachusetts law and is coupled with an interest. Each Stockholder
hereby ratifies and confirms all that such irrevocable proxy may lawfully do or
cause to be done by virtue hereof.

                  (f) Nothing in this Agreement shall affect a Stockholder's
economic or financial interest in such Stockholder's Shares and, without
limiting the foregoing, the parties acknowledge and agree that, in the event
that the Merger or any other transaction involving or affecting the stock of the
Company is consummated, such Stockholder shall be entitled to any and all
consideration in exchange for such Stockholder's Shares.

         4.       NO VOTING TRUSTS. Each Stockholder severally agrees that, on
and after the date hereof, such Stockholder shall not, nor will such Stockholder
permit any entity under his or her control to, deposit any of such Stockholder's
Shares in a voting trust or subject any of such Stockholder's Shares to any
arrangement with respect to the voting of such Shares other than agreements
entered into with Parent or Purchaser.

         5.       NO PROXY SOLICITATIONS. Each Stockholder severally agrees that
such Stockholder will not, nor will such Stockholder permit any entity under his
or her control to, (a) solicit proxies or become a "participant" in a
"solicitation" (as such terms are defined in Regulation 14A under the 1934 Act)
in opposition to or competition with the consummation of the Merger or otherwise
encourage or assist any party in taking or planning any action that would
compete with or otherwise could serve to interfere materially with, delay,
discourage, adversely affect or inhibit the timely consummation of the Merger in
accordance with the terms of the Merger Agreement, (b) directly or indirectly
encourage, initiate or cooperate in a stockholders' vote or action by consent of
the Company's stockholders in opposition to or in competition with the
consummation of the Merger, or (c) become a member of a "group" (as such term is
used in Section 13(d) of the 1934 Act) with respect to any voting securities of
the Company for the purpose of opposing or competing with the consummation of
the Merger; provided, that the foregoing shall not restrict any Stockholder who
is a director or executive officer of the Company from taking any action such
Stockholder believes is necessary or appropriate to satisfy such director's
fiduciary duty to stockholders of the Company.

         6.       TRANSFER AND ENCUMBRANCE. On or after the date hereof, except
as disclosed on EXHIBIT B hereto, each Stockholder severally agrees not to
voluntarily transfer, sell, offer, pledge or otherwise dispose of or encumber
any of his or her Shares or New Shares prior to the earliest of (a) the
effective date of the Merger, (b) the date this Agreement shall be terminated in
accordance with its terms or (c) termination of the Merger Agreement. The
provisions of this Section 6 shall not apply to the transfer by


                                       -4-
<PAGE>

gift, will or intestate succession of any Stockholder to his or her spouse or to
the siblings, lineal descendants or ancestors of such Stockholder or his or her
spouse, or any trust established for the benefit of any of them, if the
transferee agrees in writing to be subject to the terms of this Agreement to the
same extent as if he or she were the original owner of such Shares or New Shares
and the transferor shall cause the Company to place the following legend on the
certificates representing such transferred Shares, which legend shall remain
thereon until the earliest of (a) expiration or termination of the Agreement,
(b) the consummation of the Merger or (c) termination of the Merger Agreement:

         The shares of capital stock represented by this certificate are subject
         to a Voting Agreement, dated as of March 29, 2001 among the
         Stockholders named therein, CORE, Inc. and Fortis, Inc., which, among
         other things, (a) restricts the sale or transfer of such shares except
         in accordance therewith, (b) restricts the voting of such shares except
         in accordance therewith, and (c) subjects such shares to a limited
         irrevocable proxy under Section 41 of the Massachusetts Business
         Corporation Act.

         7.       ADDITIONAL PURCHASES. Each Stockholder severally agrees that
in the event (a) of any stock dividend, stock split, recapitalization,
reclassification, combination or exchange of shares of capital stock of the
Company on, of or affecting the Shares of such Stockholder, (b) such Stockholder
purchases or otherwise acquires beneficial ownership of any shares of Company
Common Stock after the execution of this Agreement, including, without
limitation, pursuant to the exercise of stock options held by such Stockholder,
or (c) such Stockholder voluntarily acquires the right to vote or share in the
voting of any shares of Company Common Stock other than the Shares
(collectively, "NEW SHARES"), all of such New Shares shall be subject to the
terms of this Agreement to the same extent as if they constituted Shares,
including, without limitation, the irrevocable proxy set forth in Section 3
hereof.

         8.       SPECIFIC PERFORMANCE. Each party hereto severally acknowledges
that it will be impossible to measure in money the damage to the other party if
the party hereto fails to comply with any of the obligations imposed by this
Agreement, that every such obligation is material and that, in the event of any
such failure, the other party will not have an adequate remedy at law or
damages. Accordingly, each party hereto severally agrees that injunctive relief
or other equitable remedy, in addition to remedies at law or damages, is the
appropriate remedy for any such failure and will not oppose the granting of such
relief on the basis that the other party has an adequate remedy at law.

         9.       SUCCESSORS AND ASSIGNS. This Agreement shall be binding upon
and inure to the benefit of the parties hereto and their respective heirs,
successors and assigns and shall not be assignable without the written consent
of all other parties hereto.

         10.      ENTIRE AGREEMENT. This Agreement supersedes all prior
agreements, written or oral, among the parties hereto with respect to the
subject matter hereof and contains the entire agreement among the parties with
respect to the subject matter hereof.


                                       -5-
<PAGE>

This Agreement may not be amended, supplemented or modified, and no provisions
hereof may be modified or waived, except by an instrument in writing signed by
all the parties hereto. No waiver of any provisions hereof by any party shall be
deemed a waiver of any other provisions hereof by any such party, nor shall any
such waiver be deemed a continuing waiver of any provision hereof by such party.

         11.      MISCELLANEOUS.

                  (a) This Agreement shall be deemed a contract made under, and
for all purposes shall be construed in accordance with, the laws of the
Commonwealth of Massachusetts.

                  (b) If any provision of this Agreement or the application of
such provision to any person or circumstances shall be held invalid by a court
of competent jurisdiction, the remainder of the provision held invalid and the
application of such provision to persons or circumstances, other than the party
as to which it is held invalid, shall not be affected.

                  (c) This Agreement may be executed in one or more
counterparts, each of which shall be deemed to be an original but all of which
together shall constitute one and the same instrument.

                  (d) This Agreement shall terminate upon the earliest to occur
of (i) the Effective Time, as defined in the Merger Agreement or (ii)
termination of the Merger Agreement.

                  (e) All Section headings herein are for convenience of
reference only and are not part of this Agreement, and no construction or
reference shall be derived therefrom.

                  (f) The obligations of the Stockholders set forth in this
Agreement shall not be effective or binding upon any Stockholder until such time
as the Merger Agreement is executed and delivered by the Company, Parent and
Purchaser, at which time this Agreement shall automatically become effective and
binding. The parties agree that there is not and has not been any other
agreement, arrangement or understanding between the parties hereto with respect
to the matters set forth herein.

                         [Signatures Begin on Next Page]


                                       -6-
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have executed and delivered this
Agreement as of the date first written above.


                                   FORTIS, INC.


                                   By:      /s/ Drew Desky
                                            ------------------------------------

                                   Name:    Drew Desky
                                            ------------------------------------

                                   Title:   Vice President, M&A
                                            ------------------------------------


                                   CORE, INC.


                                   By:      /s/ George C. Carpenter IV
                                            ------------------------------------

                                   Name:    George C. Carpenter IV
                                            ------------------------------------

                                   Title:   Chairman and Chief Executive Officer
                                            ------------------------------------


                       [SIGNATURES CONTINUE ON NEXT PAGE]


                                       -7-
<PAGE>

                                   THE STOCKHOLDERS:


                                   /s/ George C. Carpenter IV
                                   ---------------------------------------------
                                   Name: George C. Carpenter IV


                                   /s/ Jill Ann Carpenter
                                   ---------------------------------------------
                                   Name: Jill Ann Carpenter


                                   /s/ Craig C. Horton
                                   ---------------------------------------------
                                   Name: Craig C. Horton


                                   /s/ R. Gary Dolenga
                                   ---------------------------------------------
                                   Name: R. Gary Dolenga


                                   /s/ Stephen C. Caulfield
                                   ---------------------------------------------
                                   Name: Stephen C. Caulfield


                                   /s/ Joanne B. Caulfield
                                   ---------------------------------------------
                                   Name: Joanne B. Caulfield


                                   /s/ Lisa O. Hansen
                                   ---------------------------------------------
                                   Name:  Lisa O. Hansen


                                   /s/ James T. Fallon
                                   ---------------------------------------------
                                   Name: James T. Fallon


                                   /s/ Michael D. Lachance
                                   ---------------------------------------------
                                   Name: Michael D. Lachance


                                   /s/ Leslie Alexandre
                                   ---------------------------------------------
                                   Name: Leslie Alexandre


                                   /s/ David Tourangeau
                                   ---------------------------------------------
                                   Name: David Tourangeau


                                       -8-
<PAGE>

                                   /s/ Richard Towle
                                   ---------------------------------------------
                                   Name:  Richard Towle


                                   /s/ James R. Boris
                                   ---------------------------------------------
                                   Name:  James R. Boris

                                   PROXIES:

                                   The undersigned Proxies agree to
                                   vote the Shares as set forth in
                                   Section 3(c):


                                   /s/ Jerome A. Atkinson
                                   ---------------------------------------------
                                   Name: Jerome A. Atkinson


                                   /s/ Drew Desky
                                   ---------------------------------------------
                                   Name:  Drew Desky


                                   /s/ Katherine Greenzang
                                   ---------------------------------------------
                                   Name: Katherine Greenzang


                                       -9-
<PAGE>

                                    EXHIBIT A


<TABLE>
<CAPTION>

--------------------------------------------------------------------------------
             STOCKHOLDER            COMMON SHARES             OPTION SHARES
-------------------------------------------------------------------------------
<S>                                        <C>                         <C>
-------------------------------------------------------------------------------
George C. Carpenter                          318,556                   170,000
-------------------------------------------------------------------------------
Craig C. Horton                              176,218                   170,000
-------------------------------------------------------------------------------
R. Gary Dolenga                              103,000                   195,010
-------------------------------------------------------------------------------
Stephen C. Caulfield                          51,276                   137,000
-------------------------------------------------------------------------------
Lisa O. Hansen                               230,850                    31,667
-------------------------------------------------------------------------------
James T. Fallon                              230,850                    31,667
-------------------------------------------------------------------------------
Michael D. Lachance                          230,850                    31,667
-------------------------------------------------------------------------------
Leslie Alexandre                              15,000                    94,375
-------------------------------------------------------------------------------
David Tourangeau                               1,000                    36,000
-------------------------------------------------------------------------------
Richard Towle                                      0                    36,000
-------------------------------------------------------------------------------
James R. Boris                                     0                    36,000
-------------------------------------------------------------------------------

-------------------------------------------------------------------------------
TOTAL:                                     1,357,600                   969,386
-------------------------------------------------------------------------------
</TABLE>


                                      -10-
<PAGE>

                                    EXHIBIT B


All of Mr. Carpenter's Common Shares are held in a margin account at Smith
Barney. Notwithstanding any other term or condition of this Agreement, sales of
such Common Shares in connection with or in lieu of a margin call shall not be a
violation of this Agreement.

All of Mr. Horton's Common Shares are held in a margin account at Bear Stearns.
Notwithstanding any other term or condition of this Agreement, sales of such
Common Shares in connection with or in lieu of a margin call shall not be a
violation of this Agreement.


                                      -11-