Interesting observation:
"It has been pointed out that there's a mirror in every scene in which Jack sees a ghost, causing us to wonder whether the spirits are reflections of a tortured psyche."
Royalty's Opinion: the Ghosts are not reflections of Jack... The ghosts are real. A real ghost had to unlock the door in the kitchen to free Jack Torrence. Leading up to that point; Wendy hit Jack with a bat, causing him to fall down the stairs. She then dragged him to the kitchen and locked him in that huge pantry. Locks dont unlock themselves! Sombody had to unlock him. I believe Delbert Grady unlocked Jack. It sure as hell was not Wendy or Danny!!