AITA for “Firing” Her?

Context. My partner and I run a Bar & Grill in Rural AZ. He owns it. I just run Technical and Media Stuff.

Recently, my partner took a Vacation back home to the East Coast to deal with Family Issues. He left me in charge of Keys to the building, and put others in charge of their respective departments. (Lead Bartender, Lead Cook, etc)

For the duration of his absence, I was in charge of Security. Locking/Unlocking Doors as necessary, collecting the Bank Drop, etc.

His Staff was responsible for Everything Else. All went smoothly until the Last Friday, upon which there were several issues.

The Bartender in question regularly brings her Entire Family to work. Her Wife “helps” - while she is not on staff. They also bring the Kids to work, and other people are put in the awkward position of being ‘volunteer babysitter’ - there was also concerns about ‘after parties’ on the patio, after closing, where the employees hang out and drink until all hours.

It was established by the by the owner that this was Not allowed, especially while he was out of town. The employees exploited his absence and continued the behavior.

Late on a Friday night, half an hour after Last Call, I was prepared to lock the doors for the night.

First, the bartender (and her wife) were upset with me for telling them well in advance that they cannot have their kids in the bar after 8pm, per State Law, and that making them sit in the car was equally unacceptable. They needed to take the Kids Home, as there was Adult Entertainment that evening, and they had already been informed by the boss that it was not acceptable.

They got Angry, and the Bartender ultimately Quit.

The Cook, however, insisted on staying, and ordering more alcohol “to-go” - I said No, and that we were Closed for the night, and she could go to the gas station on the way home if she wanted more beers. She got increasingly aggressive and violent, ultimately threatening me with “You just wait and see what happens to you!” (When boss returns)

I, being the keyholder, essentially Fired her, and cancelled her shift for the following day, as I did not feel safe with her on the property. I technically had no right to do so, as I stated, I am not an employee or a manager. I run entertainment, and agreed to be in control of Locks and The Bank. Nothing more.

Boss was initially upset with me, because we had to close the kitchen as a result. But I felt I was fully in my right to make that call in his absence. (Further context. The kitchen closed at 8, hence no more kids, and she was Done by 8:30. The incident occurred at 11:30, after she had been drinking all night and was visibly belligerent.)

While she never worked for me, she did work for my partner, and I felt I was justified in relieving her of duty. Boss ultimately agreed with me, and the firing stands, as the behavior was completely unacceptable by Any standards, and grounds for termination. But the “grapevine” still acts like I was out of line.

Tell me Reddit. Am I the asshole?