Take it Back ! Take it Back ! is a main quest in " Fallout 3 " . It is also an Xbox 360 / PC achievement and a PlayStation 3 Trophy . It serves as the final quest in the main game , unless " Broken Steel " has been downloaded . Detailed walkthrough . Attack ! When the Lone Wanderer reaches the Citadel , Owyn Lyons will be briefing his daughter Sarah and her Lyons ' Pride , preparing for an assault on the purifier . After informing them of the situation , Sarah ' s squad is mobilized and Scribe Rothchild will activate Liberty Prime , after some initial reluctance . Prime is launched despite the objections of Scribe Rothchild , who demands it not be used and declares " . . . it ' s not ready for field tests , let alone live fire situations - the weapons haven ' t been calibrated , the navigation detection system is offline . . . " Despite his warnings , Prime is launched and used without any malfunctions . To begin the advance on the Jefferson Memorial , the player must speak with Sarah Lyons . Note that once the order to attack has been given the green light , all functions and services in the Citadel will cease . All non - player characters will spout encouraging phrases such as , " The purifier is as good as ours ! " if spoken to . If the player has anything to do in the Citadel , he or she must complete their task before commencing the attack . Following the order to attack , Liberty Prime will be hoisted out of the Citadel on a crane and the Lyons ' Pride will follow it , as should the player . Prime actually crashes his leg on the wall in the bailey on the crane , however it does not heavily damage him . Once outside the Citadel , Prime will begin stomping his way to the fallen bridge , killing everything in its path . Liberty Prime will take down the photonic resonance barriers set up by the Enclave by walking into them . Once on the bridge , the Enclave will desperately throw everything it has at the Brotherhood ' s machine : soldiers , Vertibird s , and artillery . Their efforts are entirely for naught , and Liberty Prime will annihilate everything thrown at it . It is scripted to miss a few of the troops in the confusion , however . Liberty Prime will destroy any incoming Vertibirds , so the player only needs to worry about ground troops . Targeting the ground troops can be a pain due to all the screen - shaking occurring ( Mini - Nuke and artillery shell explosions ) so V . A . T . S . is a good alternative to freehand aiming . The Lyons ' Pride soldiers will also do a fair job of mopping them up . However , keeping all of them alive will be difficult . The artillery shells tend to arc in from both sides of the bridge , but are notoriously inaccurate . Exploding vehicles are very deadly , so the player should find cover either behind Liberty Prime , or behind previously exploded vehicles . The player may feel intimidated by the concussive blasts , but will rarely take damage from them . Liberty Prime cannot be stopped , and will inexorably clear a bloody path to the Memorial . The Wanderer and Lyons ' Pride can come under attack from targets on a catwalk between buildings after clearing the bridge from the Citadel . It is possible to hustle to the near building , enter the door , run up several flights of stairs , and emerge beside the enemies on the catwalk , but this is a very impractical way of doing the job : a ranged weapon will work just fine . Melee and Unarmed characters can simply let the Lyons ' Pride finish up these troops , but they take quite a while . Either way , Liberty Prime will continue carving his way though the resistance , past the irradiated metro and onward to a second bridge . At the end is where Liberty Prime stops , and holds his position along with the rest of the Lyons ' Pride , while Sarah Lyons and the player dash inside the Jefferson Memorial through the gift shop . Note that , if one hesitates , a significant force of Enclave soldiers will be deployed nearby , either from the bridge or the catwalks around the memorial . Liberty Prime will destroy them . There is light resistance inside the gift shop , usually three or four Enclave soldiers . The player as well as Lyons should be able to clear the room . Grenades work well in these quarters . The Rotunda . After entering the Rotunda , the doors seal shut . Not locked , or pick - able , completely sealed ( there is no leaving the Rotunda after entering it ) . Colonel Autumn is waiting for the player and Lyons in the Rotunda , and locks the player in dialogue . He seems nonplussed at the player ' s arrival at the purifier . The player has two choices at this point : After resolving the situation and heading up the stairs to the control room , a panicked Dr . Li will key the intercom : Project Purity has sustained severe damage in the battle , and has become overloaded . It will soon self - destruct if the purifier isn ' t finally started , but the control room has become heavily irradiated . Final choices . Now , the game has the player make one final decision : who will activate the purifier . The radiation levels are fatal once the purifier is activated , so whoever goes in isn ' t coming out ( RadAway , Rad - X and Radiation Resistance do not matter , as it is a cut - scene ) . Decision 1 : Sacrifice yourself or Lyons . The obvious choice is that either the player or Sarah Lyons must sacrifice their life to get the purifier going and prevent the destruction of Project Purity . If the player hasn ' t figured it out from James ' notes and recordings , the purifier password is 2 - 1 - 6 ( referring to the which Catherine loved ) . If the player follows James to the purifier when he first enters the Memorial in The Waters of Life , James points out the code and repeats the passage . The player is supposed to infer it from James ' dialogue about the Lone Wanderer ' s mother , and the picture hiding his safe in the Vault 101 clinic . If the player chooses to convince Sarah to do the job , the Lone Wanderer will tell her the code in dialogue . If the player has the " Broken Steel " add - on , the player ' s Karma will be raised by 1000 if they decide to activate the purifier themselves . Karma is unaffected if the player sends in Sentinel Lyons or one of their companions . Without " Broken Steel " , if the player character chooses to sacrifice themselves , once entering the password they slump away from the purifier password panel . A statue of Thomas Jefferson is revealed inside the central chamber as it is purged . A series of still images recounting the player ' s actions throughout the game is shown . The relevant section of ending video ends with Sentinel Lyons looking at a shining pile of goo at the control chamber ' s bottom - which is , presumably , all that is left of the player . Contaminating the water . If one chooses to activate the purifier themselves , this is the time to insert the modified FEV created by President Eden into the water filter , assuming one wishes to and did not give it to Elder Lyons . As in " Fallout 2 " , the only creatures spared by the modified FEV are pure strain humans who are still within vault s and the Enclave . This would reverse a great deal of genetic damage done by the nuclear apocalypse , but at the cost of complete eradication of nearly all life on the wasteland . This decision is actually listed in the player ' s Pip - Boy 3000 as a separate quest called " Project Impurity " ; however , it cannot be completed if the player turned in the modified FEV to Owyn Lyons before departing the Citadel . Inserting the modified FEV lowers Karma by 1000 and has a long - term game impact if one has " Broken Steel " installed . The Aqua Pura thus created by purifying the water is now infected by the virus , and as the player character is not a pure - strain human as Eden believed , it will cause a negative effect on their SPECIAL stats and kill the Wanderer if four or more are consumed in quick succession . A warning will come up that reads " " Continued consumption of FEV - laced water will be fatal " " to remind you of this fact . Decision 2 : Have your radiation - resistant companion do it . Without " Broken Steel " installed , the Wanderer ' s companions will refuse to do the job . Naturally , of the seven , four would die just as easily as the Wanderer , and they are not willing to do it . Even Fawkes , Sergeant RL - 3 , and Charon who are highly resistant or outright immune to radiation , will simply decline . With " Broken Steel " , however , the latter three will now agree to do the job , as they can do it safely . Fawkes , one of the companions the player may take with them , has great radiation resistance ( or possibly immunity ) as a result of being a super - mutant . However , like any other companion character , his dialogue option has him refuse to enter the chamber , mysteriously claiming it is the player character ' s " destiny . " Companion Responses . Whether this is because Fawkes believed himself unable to survive , or if he had other reasons for declining the player ( such as feeling that the debt had been repaid , or having a genuine belief in destiny ) is not explained . Regardless , Fawkes turns out to be a red herring : the player is forced into a decision to either sacrifice themselves or make a true hero ( Sentinel Lyons ) make the sacrifice for them . Fawkes may nonetheless follow the player into the chamber if his following distance is set to " close " . If the " Broken Steel " add - on is installed before beginning " Take it Back ! " , Fawkes " will " agree to enter the chamber , stating this . Fawkes will be briefly staggered when the purifier activates , but does not collapse like the player or Sarah Lyons would . He will instead walk around the chamber and kick the purifier panel as the screen fades to white . The end will show him as " A True Hero " instead of Lyons . As intelligent as the canine may be , there is no option to have Dogmeat activate Project Purity . Instead , a new dialogue option opens up , wherein the Lone Wanderer can say some final words to his or her canine companion , stating : " I think it ' s time for us to say goodbye , old buddy . Take care of yourself , okay ? " Dogmeat whines in response . Even if you took Sergeant RL - 3 ( a Mister Gutsy combat robot , which is immune to radiation ) into the rotunda with you and command it to go in to turn on the purifier he declines and says : There is no Robotics Expert dialogue option in the conversation . Like Fawkes and Charon , if " Broken Steel " is installed before starting " Take it Back ! " , RL - 3 can be ordered to go into the control chamber and activate the purifier . He will state that his " superior design and programming " will be able to withstand the hostile environment , followed by an exclamation that " this will mean a battlefield commendation for sure . " After starting the purifier , he apparently cringes from the radiation spike , but is otherwise unharmed . The ending will show him as " A True Hero " instead of Lyons . Charon will not activate the purifier for you . The dialogue is as follows : Just like Fawkes , if " Broken Steel " has been installed before this quest , Charon can be told to enter the control chamber and turn it on . The player will remind Charon that he must obey whoever holds his contract , then order him to enter the control chamber , to which Charon grudgingly agrees . Unlike with Fawkes or RL - 3 , no mention is made of the fact that Charon , being a ghoul , should be unaffected by the radiation in the chamber . If Charon is used to start the purifier , he will replace Sarah Lyons as " A True Hero " in the ending movie . Butch , understandably , will refuse out of fear of dying and of becoming a ghoul , stating : She respectfully refuses , of course : Apparently , there are limits to Clover ' s mental conditioning and slave collar . She refuses as well : Jericho also refuses , stating simply : Decision 3 : Do nothing . . If the player chooses to , they may simply not go into the purifier . This results in Project Purity quickly exploding , along with any chance of pure water for the entire wasteland or to introduce the Modified FEV into the water supply . An ending sequence will still be played , and it will count as an ending ( obviously completing the quest and unlocking the " Take it Back ! " achievement / trophy ) . The last thing the player will see is the destruction of the purifier . Just like all other endings , this does not result in free - play . Even if the player has " Broken Steel " installed this option ends the game . With no purifier the events of " Broken Steel " could not happen . Conclusion . In all events , completing this quest will present one of the Fallout 3 endings . However , depending on your choices and the game ' s installation , the game could either continue into the events of " Broken Steel " , or simply end . Game over . The credits will roll and you will return to the title screen , if : Broken Steel . However , if " Broken Steel " has been installed and the player activates the purifier instead of allowing it to explode , the player will wake up two weeks later at the Citadel . As the Wanderer wakes up , they encounter Elder Lyons , who explains that both they and Sarah Lyons were both knocked unconscious due to an energy spike in the purifier and were found and brought back to the Citadel . Sarah has either died , if she activated the purifier , or has not yet recovered from her coma , if she didn ' t . Elder Lyons also explains the consequences of their actions , including the destruction of Raven Rock or the insertion of the modified FEV into the purifier . The first " Broken Steel " quest , " Death From Above " , starts here . Ending . The ending varies depending on how the player plays the game , and some of the largest differences are seen depending on what the player has done during Take it Back ! See " Fallout 3 " endings for more info . Behind the scenes . Liberty Prime in Take it Back ! is an example of the plot device known as , because it is introduced as a background element early on in the story , but its purpose and reason for existence are not revealed until needed .