Other mistake: After Michael kills Laurie at the beginning, he hands the knife to the inmate with the clown mask. The next kill is the cameraman for which he uses the tripod ends. A few scenes later they show Michael standing holding a knife with fresh blood on it. He hasn't killed anybody with this knife yet so where did the blood come from?
Other mistake: This is a timing mistake. In the beginning of the movie, when Michael kills the first security guard, he stuffs his head in the washer. The second security guard was in the room within 30 seconds. There is no way that Michael had time to cut this guys head off, stuff it in the washing machine, turn it on, and hide before the second guard got there.
Other mistake: When Freddy and Sara walk down the stairs after hanging Michael Myers with the camera cord, neither of them notices Jen's head lying on the floor. You'd think that they'd react in some way to this. (01:11:15)
Other mistake: When Donna is in the basement by herself, she sees a picture of Laurie cut out of a newspaper. This is a picture of her from Halloween (1978) when she was waiting for Annie to pick her up. So where did it come from?
Answer: Or maybe he's thinking that his mission to kill Laurie is done. He's been trying to kill her for a long time and succeeded. No need to continue, but when those kids invaded his house, the killing began again. No one goes into his house, but him.