Continuity mistake: When the helicopters return to base after capturing the warheads, it does a shot showing both of the helicopters coming from either side of the shot and landing. The next shot from the hangar however, shows one of the helicopters landing again.
Plot hole: When the two remaining American helicopters return from their incursion into Russian airspace, both land outside the operational HQ hangar. This is fine, except for the question of where the eight warheads that they recovered have gone to. Surely they would have brought them back to the base rather than just leave them on the bridge, but if they had, then shouldn't they either have them underneath one chopper when they both land? Or if the chopper carrying the warheads had offloaded somewhere else on the home airbase, why did both helicopters land at the same time outside the HQ hangar?
Factual error: In the end when our two heroes try to deactivate the atomic bomb, they manage to take away a little piece of explosive, so that the bomb will not do a nuclear explosion, only a conventional one. The problem with plutonium-bombs is that plutonium itself is extremely toxic when pulverised and dissolved into air. And an explosion would surely pulverise the bomb and all people (especially our two heroes being only some metres away) in the city would eventually die because of intoxication...
Continuity mistake: When Tom's friend gets shot and the other guy starts to shoot at the windshield, the bullet holes change between shots. (00:46:35)
Continuity mistake: Just before the two trains crash, there are 4 poles along the track and not far apart, then when the camera cuts to a wider shot, there are fewer poles and at a much greater distance from one another. (00:14:20)
Continuity mistake: In the subtitles for foreign speaking characters, they can't make up their mind for the spelling of the main bomber: it appears as 'Ducsan' and 'Dusan'.
Plot hole: When she checks the mails on the AOL account: Why are all mails in English? They should be in German or Russian (Problem: they use an different alphabet, Cyrillic).
Continuity mistake: In the beginning of the film the Russian officer presses a code on the back of the train carriage to close the door - the red and green buttons are at the bottom of the panel. Slightly later on when the warheads are being stolen, he has to press the code again, this time the red and green buttons are on the top of the panel.
Continuity mistake: When Tom jumps from the helicopter, into the truck that is hanging over the bridge's edge, the rope that is attached to him remains attached until Tom and Alec start fighting. Then it disappears, and suddenly reappears when Alec wraps the rope around Tom's neck. (01:14:05)
Continuity mistake: When the hijackers are setting the nuclear bomb, they drill a device to the face of the bomb, and on the right of the screen there are wires sticking out of the little silver box. In the following shot one of the hijackers opens the little silver box and pulls the wires out again. (00:12:10)
Factual error: Colonel Devoe wheel spins the Mercedes to create sparks to ignite the spilt fuel. This wouldn't be possible as the wheels were Alloys and not steel.
Factual error: Near the end of the movie, when the heroine is attempting to disable the nuclear aspect of the bomb, she spends a lot of time trying to remove one of the high explosive segments form the core, when simply cutting as many of the detonator wires as possible would seem to have accomplished the same thing. A nuclear detonation requires simultaneous detonation of all the explosive segments to cause the core to go critical. Even a small delay, caused by one or more segment not going off at precisely the right time would have resulted in only a non-nuclear explosion, which is what happened.
Continuity mistake: When the Colonel, who is carrying the nukes in the truck, has to stop at a checkpoint, he shoots two guys out at the front of the truck beyond two round small containers, but they suddenly disappear in all the following shots. (01:05:15)
Continuity mistake: When Julia gets email on her laptop in a Vienna hotel room, Tom walks up and looks at it. In this shot Julia taps quite hard on the keyboard then take her hands away from it, yet in the following shot her hands are still on the keyboard. (00:53:50)
Continuity mistake: When Tom and Julia are on the way to Vienna Tom changes seats to sit opposite Julia, and he puts his mug down with the mug's handle facing towards the plane's window. In the following shot the mug has turned around its handle is now facing Julia. (00:33:30)
Continuity mistake: When the Major and General are on top of the train just before they jump from one train to the other, the Major and General walk across the top and they pass one, maybe both, of the hijackers. When it cuts to another view, the hijackers are passing the Major and General again. (00:11:30)
Factual error: The IFOR forces looking through the Bosnian's house have Polish badges on them, suggesting that they are indeed Polish, but the one who speaks has a heavy Slovakian accent.
Continuity mistake: When Tom points the gun at the bomber who is at the top of the stairs, his brother comes round the corner, and in the distance he is walking and creeping up to Tom and Julia, yet in the closeup he is running and waiving a gun not creeping up. Also when the bomber starts to shoot at Tom, Tom and Julia get under a grid of some kind, and when Julia drops her walkie talkie on the floor, its position changes between shots. (01:43:10)
Continuity mistake: When the Russian Major is talking to the other lower ranking soldier just outside the train, in one particular shot the soldier is looking directly at the Major. Then in the following shot he is looking down at his feet, and lifts his head up twice to look at the Major again. (00:04:15)
Answer: The two train engines colliding caused the explosions, all the other cars derailed. All the warheads were carefully packed and disarmed.