Continuity mistake: A whimpering housemaid rushes down the stairway, frightened by an intruder on the second floor. Doctor Watson gallantly charges upstairs to investigate, plunging his left hand into the right side of his jacket to retrieve his trusty Webley revolver as he advances on the camera. However, the shot immediately cuts to Watson withdrawing the revolver with his right hand from the left side of his jacket. (00:29:55)