Yikes. I’d have called the cops in your situation, if for no other reason than the potential of shouting to turn into something worse as tempers escalate.
I don’t have an ironclad rule when it comes to cops, but in general, I avoid interacting with them in any way unless there’s violence afoot. I carry a non-lethal weapon so I have a means of defense if something happens to me, but I don’t trust American cops not to shoot people, so it has to be an explosive situation before I’ll engage with them.