Definitely put in for a transfer
In the second/third episode of Star Trek: The Next Generation's season one we meet new people who work in the engine room. One of these people is LCDR Sarah MacDougal. The Chief Engineer.
I would like to think the reason we no longer see Sarah MacDougal again is because she put in for a transfer. She saw everything that had happened (including what happened with Q in the previous episode(s)) and just noped right out of there. She was probably thinking that stuff like this doesn't happen on other starships.
We also never see assistant chief engineer Jim Shimoda again. I think it might have something to do with him removing all of those control chips














