So I played my finished my third or so playthrough last night and wanted to see what would happen upon waking up two weeks later AFTER turning on the purifier loaded with the FEV virus. To my surprise, it seems nothing happened at all. Fawkes and Charon and all of the Ghouls on Underworld were alive. So I take it Broken Steel renders the Project Impurity miniquest moot and void regardless of your choice? That's a damn shame. I would've wished to play on an emptier Wasteland.