IRL I believe it is against the law you cannot detain anyone due to it being deemed unlawful or something like that but I think it needs to be fully addressed because it even confuses some of the supervisors. You cannot hold someone against their will unless there is a life in danger however.
However it's been done multiple times by older staff members and senior administrators, I wouldnt really consider it violating the rules.as a civilian you can't really arrest an officer, that being said in the role play they should always follow the laws at all times, If this does not happen you should make a report and continue with the role play. The best way is to call the LT and tell him about the situation.