Of course he treated this as “not his problem” but it really was since it could have resulted in a major incident of aggression. It is very hard to deal with this sort of thing at the time, but it would seem that a tete-a-tete with the “charge” nurse afterwards would be in order, and with her supervisor if that failed.

You are not going to cure anyones personality disorder in the ER. The object of limit setting is to preserve a safe functioning environment and get the patients out of their safely–so you have to know when to set them and when not to. Doing so “to teach the patient a lesson” is never the right idea.