James Sindle (plaintiff), a 14-year-old student, was a passenger on a school bus on the last day of school. The bus was owned by the New York City Transit Authority (defendant) (Transit Authority) and driven by an employee of the Transit Authority, Mooney (defendant). There were 65 to 70 students on the bus. The students were loud and noisy, and they broke lights, windows and ceiling panels on the bus. Sindle did not participate in the destruction of the bus. Mooney made several stops and admonished the students about their behavior. After one stop, Mooney went to the back of the bus and inspected the damage and told the students he was taking them to the police station. Mooney drove in the direction of the police station, bypassing other stops along the way. Some students began jumping out of the rear side window of the bus. Sindle also attempted to jump out of the rear window, but as the bus made a right turn, Sindle fell out of the window. The rear wheels of the bus then rolled over Sindle's midsection, causing him serious injuries. Sindle and his father brought an action against the Transit Authority and Mooney for false imprisonment. At trial, upon the close of Sindle’s evidence, the Transit Authority and Mooney made a motion to amend their answer to plead the defense of justification. The trial court denied the motion and excluded all evidence related to the justification defense. The trial court entered judgment in Sindle's favor for bodily injuries, mental anguish, loss of services, and medical expenses. The appellate court affirmed. The Transit Authority and Mooney appealed to the New York Court of Appeals.