I was wondering whether or not you could kill Zimmer after Replicated Man, preferably while he is giving his speech to Harkness. I was wondering this because I feel really bad that I flushed Harkness's life down the toilet but really happy that I got the perk. I already had him give me his gun, so please don't say that I should've ended it the other way. I also already checked the wiki and was given no information on the answer to my question.
I suppose you could, if you do it before Zimmer "resets" him.
I usually kill Zimmer and his bodyguard in the Science Lab right after I've gotten the perk. Since Harkness has given me permission to do it, no one in the area goes hostile.