I noticed something weird the other day
I wanted the synth helmet, but the guy wasn't selling it, then I saw a synth in the institute wearing it. and I wanted it, so I quicksaved, and attacked him. but he didn't turn hostile until I got him down to like 25% health, neither did anyone else. SO. I laid down a couple of frag mines in front of him on his path, and when he walked over them, I shot the mines. and it killed him. but nobody else turned hostile? so, idk what that was all about, but I got a free helmet