“He’s running across the top of a train and they get to a water spout and he pushes it out of the way and jumps off the back of the train. He’s obscured by the water spout for a few seconds, and what you don’t see is that he didn’t count on the force of the water being as intense as it was, and it knocked him onto the back of his neck onto the train tracks. In that same shot — the same take — he gets up and runs off. Years later in the early ‘30s, he had a complete physical workup and they apparently X-rayed everything and his doctor said, ‘When did you break your neck?’ And he said, ‘I never broke my neck.’ And the doctor said, ‘Oh, yes you did.’ And Buster realized it was that moment on ‘Sherlock Jr.’ when it happened.”