Continuity mistake: When the garage sets on fire Freddy bursts through the door and the camera angle is over Michael Myers' shoulder and he lowers his knife in his hand and then in the next shot when you see him staring at Freddy he lowers his knife again. (01:16:30)
Continuity mistake: Sara slips and falls in a puddle of blood. When she gets up, her hands are all bloody. When she goes over and tries to open a door, they are clean. (01:17:05)
Continuity mistake: At the end when the garage is on fire Freddy shouts out, 'Happy F*****g Halloween', and when you see Michael caught up in the wires there are hardly any on his left side but when you see him from the camera there is a whole load of them surrounding him. (01:17:55)
Continuity mistake: When at his house, the first crew member Michael kicks with a camera. He puts that camera on the ground, tripod closed and laying down. When the people first walk into the house they switch to a camera view that's up the stairs and you can see that the camera that was laying on the floor is now propped up against the wall.
Continuity mistake: Freddie is stabbed rather harshly on the shoulder but there is no blood anywhere on his shirt or anywhere near his wound.
Continuity mistake: At the party, when someone screams out to turn the volume down, right behind the kid that plays Decker is a blonde haired boy with a red smoking jacket. It then cuts back to inside the Myers' house for a few minutes. When it cuts back to the party that same blonde haired boy just walks in as if he wasn't in there before, asking what they are watching.
Continuity mistake: When it flashes back to how Michael Myers survived the end of H20, we see the paramedic that he subdues and switches places with. That paramedic had a bit of a stomach on him, yet the figure of Michael Myers throughout the rest of H20 after the switch remains the same as the real Myers. [A side note: Halloween H20 WAS intended to be the absolute final film, but popular demand forced a return and obviously they needed a scapegoat excuse to bring Myers back. Still...]
Continuity mistake: When Donna puts her shirt on after messing with Jim, she doesn't put her bra on. After Michael kills her, her bra is back on.
Continuity mistake: In the first Halloween the kitchen of the Myers house is to the right of the back of the house, but in this one it's to the left.
Continuity mistake: The blonde girl has very thick black roots. She is decapitated. When Michael throws her head down the stairs, she is perfectly blonde, no black roots.
Continuity mistake: When Michael Myers is walking towards his sister's room at the mental ward, the camera shot is behind him, as he holds his knife by his side. The camera angle changes to his front, and now the blade is at his front.
Continuity mistake: When you see Sara driving up the school path on her moped you see a lonely girl sitting on a bench and when it changes to the next shot she is gone.
Continuity mistake: In the end, when Busta Rhymes is smashed into the wall, his dreads are really a mess. Next shot his dreads are neat. And the 3rd shot of Busta, his dreads are a mess again.
Continuity mistake: We see countless times that there is a wooded area behind the Myers home (especially after the house burns down, it is seen more clearly). But in the other films, the Myers home is in the middle of a residential neighborhood. Behind his house would be the back of another house.
Continuity mistake: After Sara and Freddy walk down the stairs after Michael Myers is hung, the curtain on the door behind Sara changes between shots, even when they peek through it.
Continuity mistake: When Michael first gets his head cut off by Laurie the eyes of the severed head are clearly wide open. (in H20 and in flashback scene) Then when they remove the mask from the head, not only is the mask suddenly and noticeably different, but the eyes are now closed.
Continuity mistake: When Rudy is in the kitchen, he tries to open a door but it's locked. After Michael pins him to that same door, he opens it right up and walks through.
Continuity mistake: In the garage, Sara falls into a cart with equipment on it. It tips over easily yet the equipment lands on Sara's leg and she's unable to move.
Continuity mistake: Halfway through the film, we see Michael Myers walk into a room immediately followed by another Myers. Both are dressed nearly identically in a blue jumpsuit. But as soon as the first one turns around and we learn it's actually Freddie, the shot changes to Michael and back to him and he's wearing his jean jacket, seen in the rest of the movie.
Continuity mistake: When Michael Myers has Sara cornered, he rotates the knife in his hand so the blade is pointed down. After being knocked backward by Freddie, Michael advances forward and once again rotates the knife to point the blade down, yet he never changed it back.
Answer: At first impression, Laurie was catatonic not only from the shock of killing an innocent man, but also from a lifetime of being chased down by her murderous brother. She obviously knows from past experiences that nothing she does (including faking her own death) will stop Michael from finding her. It is later revealed she has been faking her mental issues (think when she has been hiding her regular meds in the raggedy Ann doll) and is committed only to stopping Michael, no matter what the cost. She may have also been trying to protect her son and the only way to do that is to allow herself to be institutionalized in order to lure Michael there.