Continuity mistake: The miner wounds Sarah's right forearm during the supermarket chase and the medic bandages it up. Yet, in all subsequent scenes, her arm is fine.
Continuity mistake: In the final mine scene when "Harry" is walking toward them and popping light bulbs with the pickax along the way, the second bulb he hits causes the wire to swing down and swing back and forth. In the next shot, the wire is back up on the shoring post. (01:32:20)
Answer: He had a psychological disorder which was triggered by the attack from Harry Warden. If I recall correctly, he developed a split personality.
ChristmasJonesfan