Quick breakdown. That was the Aqueduct station, which means that was the A train, so they was either heading to/from Far Rock. Secondly, nobody is trying to stop a fight, once a fight happens, they have to contact the crew, then the crew has to contact control center, who then in turn contacts the police, meanwhile the train has to stay their until police and medical assistance arrives on the scene. That's why the lady was telling them to get off the train, cats ain't time for that, people are trying to go about their business.