Personally I think he either A
Escaped and decided to do a new name and face (if that's possible)
B- guy's dead
C: Kathleen basically kidnapped him and went to town BDSM style and given to Sophia
A: I mean it possible but relies on him knowing someone (outside of the club) that could help him "get out" before kathleen realized he had seen/done whatever he did. The way Ian describes him makes me think that he could "know a guy" the biggest "issue" is it relies on him abandoning the house girl he fell in love with (apparently wanting her to get out was the "thing" he did) but he could just value his life over pussy
B: Boring unless Edwin/Ian/the reader get to see the body/reactions to it imo, we already know that Ian is "less on board" with the whole thing after learning about the bug/van doren/his other friend even if he is never brought up again Ian would still get "less on board" with thngs as they escalate (potentially even more so if he is introspective). IMO reveling his friend was killed just speeds that up
C: I think kathleen could already go to town on him if she wanted?
Ian mentions that he would let you know if he thought something was dumb but im pretty sure kathleen could just say "assume the postion" and unless he wanted to lose his job (and the house girl) he would?
What we have now: Kathleen mad at him because blackmail/him talking back/being closer to an "ian" at work than an "Edwin", Kathleen needing people to conduct underground human expierments with van doren/Sophia (sorry turret), The club not being an "offical" place and being one that employees people that would not be "missed" as much or as quickly (He hadnt talked to his mom/family in a long ass time, the house girl was a house girl at an illegal brothel.....), and downright confrimation that someone (female?) is down in a secret part of the club and is beggng to be free'd (or whatever they were screaming about its been a minute). IMO it makes sense for kathleen to get rid of him and she has a way too do it that doesnt invovle leaving the club, and that benifits her other ventures (the drug). Even more so if the person we heard was a feamle since youd want a male just for more data points.
Edit: Didnt Ian mentuon kathleen doing butt stuff with him at some point?
if she can massage Ian's porstate im sure she could get some random from Hawaii doing whatever she wanted