Continuity mistake: When Helen is about to enter the hotel room she tears her dress' right sleeve off. The strap of her bra is either fallen over her arm or correctly placed over her shoulder, depending on which angle focuses. (01:18:15)
Continuity mistake: The position of the champagne bottle holder and the next chair changes between shots. When Michelle enters the room and the camera is placed in the bedroom, the bottle holder stands between (and somewhat behind) the chair and the window wall. When Michelle approaches the table (camera is now Michelle) the chair is between the bottle holder and the window wall. Later, at the end of the scene this changes again, depending on where the camera is. (01:19:50)
Continuity mistake: When the terrorists burst in on Jamie and Arnie in the hotel room, the positions of Arnie's hands change between shots. Once going from being by his side to one being behind his head instantly. (01:26:25)
Continuity mistake: When Harry picks the handcuffs right after he receives the truth injection, he still has the handcuffs hanging off his hand. After he kills the guard with the hook, he grabs Helen and says "let's go". He doesn't have time to take the handcuffs off his hand but they are gone. (01:40:10)
Continuity mistake: After Helen drops the MAC-10 down the stairs and it keeps shooting, killing all the bad guys, you see it hit the floor, then the shot changes and it stops on the stairs. (01:46:10)
Continuity mistake: Throughout the limo chase scene, Tia's scratch on her face disappears and changes from cheek to cheek. (01:49:10 - 01:56:00)
Continuity mistake: During the bridge scene the limo driver is shot and blood splatters on the windshield. In the outside angle the blood is gone. (01:55:20)
Continuity mistake: During the bridge sequence, the limo drives through an area that is on fire. After emerging from the fire, the passenger side headlights are shown to be blackened from the smoke and heat. Further down the bridge the headlights are shown to be clean and new looking again. (01:56:40)
Continuity mistake: The scene in the SUV where Harry asks Tom Arnold 'if there is anything new', and he answers 'no', you see that they were driving straight, but when the camera does a wide shot, you would see a building directly behind them which means they would have been driving through the building.
Continuity mistake: When Harry goes over the Marriott hotel roof, he switches from being over the "a" to being over the "r", depending on which camera angle it is.
Continuity mistake: When the limo is on the bridge and it runs through a burning part, the pavement is filled with debris scattered all around. When Harry's chopper flies over the place, the pavement is clean.
Continuity mistake: Before Salim Abu Aziz kicks the bathroom stall doors, we can see there are 6 stalls (and Harry is in the 6th one). Salim kicks the first door, but the close up shot shows it's at least the 2nd door since we can see a door to the left of the post with the lock on it. After that he kicks the 2nd and 3rd door. After he kicks the 4th door, Harry crashes out of his stall, but he's 3 stalls over instead of 2.
Continuity mistake: When Arnie leaves the snow hill and meets the van, snow suddenly appears on his right shoulder, between shots.
Continuity mistake: When Harry and Gibb realize they are being followed by the station wagon, they and the terrorist pull over in front of the sidewalk twice.
Continuity mistake: When the wall is taken off Simon's trailer, he falls on Helen and he knocks the champagne bottle off the table in the process. When Harry knocks the table aside, the champagne bottle is back on it.
Continuity mistake: When Helen is inside the caravan the way she holds the glass changes between shots.
Continuity mistake: During the fight in the limo between Jamie and Juno, some stray shots go through the roof, creating obvious bullet holes. They change quantity and position a few times in the subsequent shots. Also, in the shot when Arnold lifts Jamie out of the limo and it takes a header into the water, the bullet holes are completely gone.
Continuity mistake: After Juno Skinner has killed her limo driver, the limo speeds out of control. There are two champagne glasses in the cup holders next to Juno, but both glasses disappear and reappear between shots while Juno and Helen are fighting each other. With the limo speeding across the bridge, it doesn't make sense that Juno's gun stays on the roof for a while. The gun should have slid off the roof when the limo banged into the guard rails. It doesn't fall off until after the limo has passed through the flaming truck wreck.
Continuity mistake: When Jamie first enters the hotel room, she moves up to the table with the champagne on it. But, moments later, she proceeds to move up to the table again, right before Arnold says hello.
Continuity mistake: When Jamie Lee Curtis and Tia Carrere are fighting in the limo, their hands can be seen wrestling for the gun on the roof in one quick shot before that action actually happens.
Chosen answer: He didn't really. Harry just knew he was heading up. He pressed the top floor to get the elevator moving and kept an eye on him on the way up. If the terrorist's elevator suddenly stops, Harry can press the button for that floor to stop his elevator.
XIII