Aileen had her phone, but it was turned off, so we walked across the street and onto the far corner while waiting for her phone to come on so she could call 911. When we turned around, the guy who'd been being chased was on the ground in the middle of Beach St, and two or three guys were kicking him, and hitting him around the head and shoulders with what looked like a baseball cap, but in retrospect, having overheard some of what people who were closer saw, I think it may have been a bag with a gun in it.
Aileen finally got through to the proper police (initially, she got through to someone who had to put her through to Boston? I'm unclear on how all of this works.) and reported what had happened, and the guys who were doing beat up seemed to scatter at that point. I went over to the guy who'd been beat up, but there wasn't a lot I could do to help, other than make sure that he got out of the middle of the street. Needless to say, it was very messy and he was in terrible shape. He kept asking, "Who hit me? Who hit me?"
By then, it seemed like there wasn't much for us to do, so Aileen and I continued on our way, but when the police FINALLY arrived, we were back at that corner, so we talked to one of the officers who was there. Of course, by then, no one was around, even the badly beat-up guy, so the police response looked totally overblown, but if they'd only arrived sooner...
So, we're fine, but I feel dissatisfied with what I was able to do to help the situation. Unlike the fight last summer that I was able to get in the middle of and break up (between 2 women, not 15 men), I didn't have anything useful to do here, so I feel unresolved about the whole thing. I think the only safe and useful thing I could have done would be to pay more attention to what was happening, and where the various parties WENT when they disappeared, but I didn't even manage to do that.