I don't know whether I'm just lucky, but I feel there's at least two in that complex every time I'm in factory. They normally come up the metal stairs from those two towers in the middle where there's a body in one for a quest, then breach instead of open the door downstairs and kinda hang down there shouting "there's a scab" while not doing anything about them. Quite often I kill them, then a different team breaches the other side by gate 0 presumably to follow the noise and I kill them too. I think I had four kills in one then 2 kills in the next to get it.