Corrected entry: Near the end of the film when Lockhart is packing up and leaving because he doesn't want to go into the chamber. Look closely in the mirror next to the door just before Harry and Ron enter the room. You can see Lockhart watching the door waiting for the boys to come in.
gandolfs dad
12th May 2003
Correction: Lockhart was jumpy because it could have been one of the teachers coming. He would have heard Harry and Ron's footsteps. I think that would draw his attention to the door.