If you can hear them at that distance perhaps it's a situation where a polite call to the cops is warranted? I'd hate to have the next set of sounds be those of physical rather than verbal violence. But that's just me.

The one time this happened to me I was walking home (to my then apt in Cambridge) from the T and quite clearly heard a male voice screaming threats of violence, and a female voice responding with foul language. I went home and called 911. Dunno if that was "the right" thing to do, but it seemed so at the time.