Yesterday, a lunchtime fight broke out in SoHo when a 16-year-old student stabbed a 12-year-old schoolmate. The assault took place at the intersection of Grand Street and West Broadway near The Door, an alternative private school where “troubled” kids can spend a year if they’ve been suspended from city schools. One witness told the New York Post that he saw about 12 kids arguing. The younger of the two students involved was taken to St. Vincent’s Hospital and is said to be in stable condition. The older was arrested and the weapon retrieved.