I've run into a weird main quest bug I don't see listed on the wiki.

I just bought Broken Steel and went to try it out, forgetting where exactly I was in the main quest, and when I went to look I noticed that the Take it Back! quest was blanked out even though I obviously hadn't finished it and ended the game. Strangely, the "Cycle the airlock" and "Activate Project Purity!" items aren't filled, either.

To investigate I went to the rotunda at the Jefferson Memorial and found Colonel Autumn and his lackeys dead in the room, as if I'd won the endgame, and the first airlock to the Purifier will open but not the second. In addition, after any amount of time in the rotunda room there will suddenly be a flash like the dead Autumn is flashbanging you as in one of the cutscenes, but obviously not he nor anyone else is there to continue the scene. I (and Charon) remain frozen in place and I have to reload a save.

Any ideas on how to fix the quest/access the DLC without reloading far-gone saves?