If you are able to verbalize what constitutes assault, vs. battery, and how the two progress, and if the patient is lucid, just call the Police.
I have no idea what the situation was, obviously, but it would not be unheard of for a supervisor to escalate a non-compliant patient's behavior(in a controlled, intentional manner) to have the patient removed from a facility, but for yuks & giggles, it is unacceptable.
My thinking is, if it was serious enough for you to post, its serious enough to follow through. If this was "venting", it was very ill-considered, as you've stated refusal to comply with your duty to report.
...and Esme got there first.
Okay, I just ran across the related post. Psych facilities are their own world, and I would pretty much say you're SOL, assuming
what you saw qualified as A&B. Knowing that 2 RNs and 2 aides have been assaulted & battered at our local facility, one resulting in a permanent spinal injury, because of the facility's "no intervention" policy with the residents, I have a feeling I might understand where the super was coming form; maybe not, but if the monkeys run the zoo, and know it, playing screwhead with them may be one of the last ways to retain some measure of control.
YMMV, I do not know your facility, this response is biased by personal experience, etc., etc..