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Walkthrough

This is a fairly short and simple quest. It's also the final main quest in the game. Barring what might change in an upcoming DLC, completing this quest will end the campaign, so it's a good idea to save your game before starting, just so you'll have a place to come back to, provided that you're interested in visiting more optional locations or completing more side quests.

To get the quest rolling, you'll need to tell Sarah Lyons (in the Citadel laboratory) that you're ready to go. This will cause her and the rest of the Lyons' Pride, plus the giant mech Liberty Prime, to start heading for the Jefferson Memorial. Sarah and the mech can't be killed, and they'll have no problem with the enemies and obstacles in their path, and so you won't need to do anything in this portion of the quest, other than tag along.

When you reach the Jefferson Memorial, Sarah will enter with you, and Liberty Prime will (obviously) stay outside. You'll have to kill a few Enclave soldiers in the gift shop, but it shouldn't take you long to make it to the rotunda, where the control room is located (#1).

Inside the rotunda, you'll meet up with your old friend Colonel Autumn. If you can pass a couple of speech or intelligence checks, then Autumn will leave peaceably. Otherwise, you'll have to kill him and the two Enclave soldiers with him. If you choose the latter approach, then you'll find Colonel Autumn's Uniform and Col. Autumn's Laser Pistol on his corpse (although the pistol might end up on the floor somewhere).

Once you've removed the Enclave threat, Sarah will get a call from Dr. Li, and you'll learn that the purifier must be turned on now to prevent the building and Project Purity from blowing up. Worse, Dr. Li will tell you that the control room is filled with a lethal amount of radiation, and whoever turns on the purifier will die.

There are three ways that you can deal with the purifier (and end the game):

• You can turn on the purifier yourself. You'll die if you do this, but you'll save Sarah. The code for the purifier is 216 (from Revelation 21:6, your mother's favorite passage in the Bible).
  
  
• You can force Sarah to turn on the purifier. For this case you'll just need to activate the airlock control to let her inside.
  
  
• You can do nothing and let the building blow up. Since there isn't any way to leave the control room, this option will kill you as well.

Just outside of the control room you'll find an auxiliary filtration device. If you have the Modified FEV Virus from President Eden, and if you want to use it, then this is where you should put it. You can reach the device regardless of your choice with the purifier. You'll just need to run over to it quickly before the building blows up.

Once you've made your choice with the purifier, the ending cinematic will start up, and you'll learn how your actions in the game have affected the wasteland, and vice versa.


1 - Control Room


Exits:

1. Exit to the wasteland.
2. Doorway between the Museum and Gift Shop and the Rotunda.