What is an acceptable level of anger to have toward someone who might be bi-polar when they act out?

This girl might be bi-polar not really sure at this point but long story short, here’s what happened…
This girl visiting from NYC, let’s call her Sally, was really nice at first, but started to let off a vibe that she wanted my g/f and I to go home, I assume b/c she wanted to hook up with the other guy there. (my g/f drove, we walked to the bars, now we’re back hanging out at a friends apt, everyone else went to sleep) She was nice about it at first, asking things like: “Is it a money thing? you guys can’t afford a cab home?” I explained my g/f was waiting to sober up. A few mins later Sally stood up, commented that she was starting to feel a little buzzed, walked to the bathroom where my g/f was and said “Listen whore, you need to go the f——home!” Argument ensues… Sally comes back and now addresses me: “You need to get your whore and go the f——home!” Argument ensues…

So this was completely out of nowhere, everyone had been getting along the entire night, the girls were actually very fond of her before this happened. Her having mental illness is purely speculation at this point but if that is the case, I would understand that she might not be able to control it but at the same time I’m obviously not happy with her actions. What is an acceptable level of anger to have towards this person? If it turns out there’s nothing wrong with her then I guess she’s just a total bitch.