Well if she was a girl and it was guys beating the living crap out of her.. i'd definatly call the cops... and then run over there and beat the crap out of those guys with my kung fu.
now if it was a guy getting beat up.. and assess the situation ( knock on some doors, look around for tools like a ninha would).. and then maybe run over there swinging and throwing.
yeah this reminds me of a time I was at a show a band was playing at. I was inside while it happened, but someone came in later and told me that some guys was slapping a woman and dragging her or something and everybody outside was just watching. I may not be "built", but I def. couldn't stand by and watch that happen. I would have grabbed some bigger friends of mine, had them back me up and then at the last minute, ran away. haha. but seriously, strength in numbers. you don't have to even lay your hand on someone to stop a situation like that.
everyone was just watching ? freakin' losers ! i can't stand watching a woman get hit. it's wrong.. its just retarted.