Continuity mistake: Alex opens the closet to get his mum's coat, and the big red boxing glove springs out. He then picks up a black pole from the floor in a closeup ... which wasn't there in the previous wideshot. (00:56:30)
Continuity mistake: When the villain with the long hair is being electrocuted by the wire outside the front door, in a close up shot his ski pants are on fire, then in a further away shot, they are not, then in another close up they are on fire again. (01:03:05)
Continuity mistake: After the trunk of books has fallen on Beaupre and Unger, Unger leans upright and has a blue book on his chest. When it cuts the book is light brown. (01:06:30)
Continuity mistake: When Mr. Beaupre takes the control car apart, he holds the bottom of the car which has the wheels on it in his left hand, and the top of the car in his right hand. The shot changes and the two parts of the car have swapped over into the other hand instantly. (01:25:45)
Continuity mistake: Mr. Beaupre is talking to Alex in the garage, and Alex walks backwards away from him, he nearly touches the wooden shelf behind him. When it cuts to a wideshot Alex is now much further away from the shelf, and when it cuts to another closeup he once again walks back into the shelf. (01:29:16)
Audio problem: Near the end of the movie when the parrot is going to light the firecrackers, he is talking perfectly even though he has a match in his mouth. (01:30:35)
Continuity mistake: When Alex's Dad arrives home at the end of the film, he hands Alex a remote control car box. Between a wideshot and closeup the box turns around 180° in his Dad's hands. (01:32:10)
Continuity mistake: When Alice does flips to try and get on to the back porch of the house, her hair is different after she turns around to walk towards the door.
Continuity mistake: When the leader of the robbers is looking for the chip he rips the car apart across the street in Mrs. Hess's house. He doesn't find it. About five minutes later the parrot is riding the car into the snow fort and again in the house.
Other mistake: When one of the bad guys looks through the mail box slot, Alex sprays him in the eyes with black spray paint. Meaning the spray paint must have actually gone INTO his eyes, yet when he turns around, its only around the outer part of his eyes and nowhere in his eye balls.
Plot hole: The main criminal puts on the "butt inspection gloves" whilst searching the first house, but when Alex sees him through the telescope he pulls down the blinds and has black gloves on. Returning outside, they revert back. However, how does Alex know the criminal donned the rubber gloves (when he describes him to his mother), if he saw what we saw through the telescope - the black gloves?
Continuity mistake: A little way into the film, Alex is talking to his mum in bed whilst she is applying lotion to his chickenpox. One moment his shirt is open, the next it is buttoned up and closed, but there was no time for his mum to do it up, it happened in a split second.
Factual error: During the remote control car chase the bad guys' minivan drives directly over it at one point. From the view of the toy car, you can see a driveshaft running down the centre of the undercarriage, which would be impossible on a front-wheel-drive vehicle like the Nissan Quest they're driving, which use half axles to drive the front wheels.
Factual error: When the criminals are supposed to be in a San Francisco airport, the scene was quite obviously filmed in Chicago's O'Hare airport. They then cleverly catch a flight to Chicago, and then come out at a different part of the O'Hare airport.
Continuity mistake: After Alex calls the police the first time, his mother herds him into his room. When they first enter there is a shot of his bed, the top pillowcase's open end is first facing right. Then there is a close up of Alex and the open end is facing left. It continues switching to the right whenever the shot is from farther away, to the left when it's a close up of Alex.
Continuity mistake: When the FBI are rushing to reach Alex, as the snowploughs sweep the spy's car aside the front plough sweeps to the left. Further down the street the front plough sweeps to the right.
Continuity mistake: At the end, when the parrot is going into the igloo, the igloo looks tiny from the outside, as if Alex would barely fit in there. But when the parrot goes into the igloo, the man can fit in there and there is so much more space in it.
Continuity mistake: Alex's mother goes to make him a sandwich and squeezes jelly onto the bread. The shot comes back after both Alex and his mother talk before she goes out. The jelly has mysteriously been spread.
Continuity mistake: In the very first shot of the Mom, she carries in a load of boxes. Two green ones are included, one with writing above the other. When she unstacks them, the shot pans out a little bit, and the boxes are positioned differently.
Continuity mistake: When Unger gets run over by his criminal partner, look at the driver side window. Making initial contact with the car, it is closed. For the close up shot, it's wide open, and when the car turns, it's only open a couple of inches.
Answer: It was Jernigan who thought there was a woman in the shower and he couldn't take the risk that if it was a woman, that she would eventually get out and see intruders in the house and call for the police. The only option open to Jernigan would be to kill her so there'd be no witnesses.
No it was Beaupre who thought there was a woman in the house.
I've seen the movie and I can confirm that it was Jernigan who opened the shower curtain because he thought a woman was in the shower.