Assaulting the Enclave

Exit the Citadel and head north towards the Jefferson Memorial. Stay clear of Liberty Prime as he advances, picking off Enclave Soldiers.

Cross the bridge over the Potomac, keeping your distance from Liberty Prime to avoid missile fire.

On the eastern side of the bridge, turn south and head downhill under a sky tunnel. Continue south until buildings block your path, then turn west and follow the riverside road south until you reach the bridge to the Jefferson Memorial. Liberty Prime will clear the barriers.

Engage the Enclave Soldiers in front of the Jefferson Memorial, then enter the Jefferson Museum and Gift Shop. Fight your way to the Rotunda.

Confront Colonel Autumn and his two Enclave Soldier escorts (one with a Minigun, one with a Gatling Laser). You can choose to kill him or let him escape.

After the confrontation, Doctor Li will announce that the purifier needs activation, but the area is highly radioactive. You must choose someone to enter the central area of the Rotunda to activate it: yourself, Sarah, or Fawkes (if he is with you, as he is immune to radiation).

Before activating the purifier, decide whether to insert the Modified FEV into the “Auxiliary Filtration Input”. This is considered an evil act and will change your Karma from Very Good to Neutral.

If you choose to activate the purifier yourself, enter the code “2-1-6” in the central area of the Rotunda. This will trigger the end of the main game.