Factual error: The terrorist with the AK47 is unaware of the fact that a Harrier is hovering just outside the window until he slowly turns and see it there. He does a double take when he sees the Harrier just five metres away! A Harrier is an incredibly loud aircraft; you can hear them from three kilometers away. At that range the floor would shake with the noise and he would have been in no doubt whatever that he had been under attack for some time.
Revealing mistake: When Helen Tasker pretends to be the hooker, Doris, at the hotel room, she does a striptease and you can see a burn scar on her right hip from a childhood accident. Then it is gone during closeups, as a body double is used.
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.
Factual error: Throughout the entire movie, Arnold and Tom are always riding in the GM S-series SUV. The thing about these vehicles is that they came with different side view mirrors and if you look close enough during all the shots with the SUV, the side mirrors on the side change, from small ones to big square ones, showing that two different GM S-series SUVs were used throughout the movie.
Revealing mistake: When all the terrorists are firing their guns at the sky near the end, one of the men is clearly pulling the trigger, and empty cartridge cases are coming out, but there is no muzzle flash like the other guns.
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.
Revealing mistake: When Helen drops the machine gun down the stairs and it starts shooting, watch the railing with the broken splinters and you'll notice that we are always seeing the very same shot repeated over and over again.
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.
Revealing mistake: More rounds come out of the Vulcan than are carried by real Harriers.
Other mistake: In a scene where Gib and Harry are getting into their car, if you look very closely you can see a elderly old lady staring into the camera.
Factual error: In the amount of time it took for Arnold to exit the lake and infiltrate Khaled's party, the mere temperature in the mountainous region would freeze the hole over long before the patrolling guard would come across it. It might not be fully frozen, but enough to be mistaken for being normal to the casual observer.
Factual error: When Arnold's harrier hovers up and a terrorist has to adjust the focus of binoculars, it shows Arnold's face. Being so close, there would be no way binoculars would have a clear view of his face, maybe a blurry eye at best.
Audio problem: When Helen drops the gun she moans something like "Ow! Ew!" but her mouth is closed.
Visible crew/equipment: When Helen tells Harry she slept with the plumber and he kisses her goodbye, watch the reflection on her glasses: When Harry walks out to the right, a crew member standing in front is very noticeable.
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.
Plot hole: Harry goes into the Mall, and two of the terrorists follow him through the Mall, up the escalator, down the hall, and into the men's room. Then the third terrorist leaves the car and follows exactly the same path to where the other 3 went, even though there's no way he could have known exactly where to go.
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.
Visible crew/equipment: The first time we see Salim Abu Aziz on the Florida island, he has his back to the camera and turns around. The shot comes closer to him. The camera shadow becomes visible on him at that time.
Chosen answer: He just exclaims, "Shit!" It's not what he says that makes the henchman let him go, it's that they both realize that if they don't find cover they'll both likely be shot by this random, firing Uzi.