The video is probably a bit confusing, so we’ll try to explain it step by step:
At 0:23 one of the drunks gets pepper-sprayed. You can see him standing on his knees on the floor and whimpering at 0:34, as the result.
At 0:40 his friend is trying to take him out on the street. Then, at 0:52 a strange thing happens – the guy whom the other four were beating up when it all started, comes back into the subway and breaks a bottle over the wall, preparing himself for a fight.
Our guess is that he was so drunk, that he didn’t remember who beat him up, or that the other four were his acquaintances, and he decided to take their side despite the circumstances (again, because he was too drunk to think clearly.)
The worse for him, for his so-called “friends” knock him down again at 1:21, which we then replay for you in slow motion.
After that, the cops show up and everything ends.