Would it be so bad to tell the resident who was locked up against their will that you thought the situation was poorly handled? Institutions are not monoliths and just because you're staff, you don't have to agree with every decision that gets made. It can be very powerful and healing to hear that someone in a position of (relative) power saw what happened.

Also, what are the mechanisms for incident reporting where you work. Can you flag a situation and trigger a review?

I'm sorry your T responded by basically telling you to get used to it instead of validating that it's horrible watch power being abused like that.