In Punch, we also saw the buildup to and impulsive enactment of the pivotal crime. In Mass, it’s not even named until we’re 30 minutes into the 90-minute running time, though by then we’ve picked up heavy hints of its general shape. Seven years ago Hayden, the teenage son of Linda (Monica Dolan) and Richard (Paul Hilton), killed ten students at his high school with guns borrowed from a friend, before shooting himself.