Trouble on the line

Last night on the el home, I was sitting in one of the ends and facing forward. The two forward-facing seats to my right and the one behind me were all singly occupied. I had my nose in book, so I hadn't paid a lick of attention to anyone around me. Suddenly, I heard behind me say in a sharp voice, "You look bald to me." I couldn't understand the response. He continued, "You're looking pretty bald to me. Did someone tear your hair out?" I began to wonder if the man behind me was mentally retarded, because I couldn't figure why else one would address a total stranger in this way. That soon became clear as the guy reacted defencively to the next response: "I'm allowed to look, ain't I? It's a free fuckin' country." At this point, I was dying to get a better view of the participants but I didn't want to turn around lest the guy start laying into me. Especially when he said, "You keep looking at me. Keep looking, I don't fucking care." I never understood a word the other man said, but the first man's statements only got more and more belligerent. "You're not from around here, are you? Where you from, Brazil?" The other man had stopped answering. Before the bully could escalate things, the train reached his stop and he got off. He was a thirtyish Caucasian with a short blond moustache and hard expression wearing a ball cap and a sweatshirt. I then turned around to look at the other guy, who turned out to be a middle-aged (or prematurely balding) Hispanic man with a thick black 'stache wearing a white shirt, dark tie, and slacks. I said some words of sympathy, about how the other guy seemed to be looking for a fight. A red-haired Russian matron in the seat ahead looked warily at us but didn't say anything.

As we paused at Berwyn, I saw a short, elderly lady being yelled at by an equally short, stocky, somewhat younger- and wilder-looking, brown-skinned man. Twice I saw him add emphasis to a point by pressing down on her arm in an agitated fashion. For a moment, I considered jumping through the doors and investigating. She didn't look frightened, just concerned, as she apparently made mollifying responses. When the train began moving I saw that there were plenty of other people on the platform only a few feet away and consoled myself that one of them might at least fetch and attendant of the man became violent. Then again, the fate of Kitty Genovese is never far from my mind. As I got out at the next stop, I pondered what I would've done if the belligerent behind me had assaulted the other man. I suppose run to the call button and told the conductor to stop the train and call the police. But what then?