In a park, at night, as a train screams nearby, the teenagers punch, kick and grapple. They roll over and over, gravel sticking to their rain-soaked clothes, in a terrible embrace, beating one another bloody. “We didn’t want to romanticize it or sugarcoat it or make it easy,” the director Danya Taymor said of this scene in the Broadway musical “The Outsiders.” “It felt really important that these moments of violence be terrifying, be brutal.”