Continuity mistake: The mine is 600 meters deep. Deakins offloaded the bomb at ground level, started sending the elevator down, and then dropped two hand grenades down the shaft. In the next clip the elevator is at the bottom of the shaft, and the grenades hit the bomb. For that to happen the elevator must have free-fallen to the bottom, not descended as we see it.
Plot hole: In the mine shaft, with the lift going the speed it does, it would take over 10 minutes to travel 2000 feet. Yet our characters manage to do it in about two minutes (use the bomb timer for reference). With the bomb timer starting at 30 minutes (not to mention Travolta puts it down to 13 in a later shot), everyone in the mine should be dead before they could escape.
Factual error: EMP is mentioned as a threat, but only atmospheric blasts generate EMP fields that affect large areas, not subterranean detonations.
Factual error: When Travolta is deep down in the mine shaft, he uses a two-way radio to talk to his guys upstairs. I know from personal experience, and from being in the military that two-way radios, no matter how much power output they put out, cannot talk for more than 100 feet max in an enclosed area such a mine with thick walls, let alone 2,000 ft (the distance the elevator travels in the mine).
Continuity mistake: Toward the end of the movie, after the nuke has been armed in the mine and both groups are driving Hummers, John Travolta switches off the engine and informs his passengers that when the nuke goes off, the electro-magnetic pulse (EMP) will disable any vehicle that is running. Little does John (and apparently the movie's director) know, but EMP will fry any and all electrical circuits, whether or not the vehicle is running.
Factual error: Despite what movies keep telling us, you cannot manually arm a nuke taken from a missile or bomb. A device called an accelerometer measures the speed of the flying/falling weapon and arms the warhead. It cannot be done on the ground. The warheads are specifically designed to make stealing a warhead and arming it by itself impossible. Deakins is a pilot, not a nuclear technician. He would need to disassemble the nuke and rebuild it completely to make it detonate. These features are designed so that bypassing/disassembling them DISABLES the nuke completely, making it completely unusable for just this reason.
Continuity mistake: When the helicopter on the train blows up, the boxes that Deakins is hiding behind are on fire. When Deakins stands up, the boxes are not even touched.
Continuity mistake: When Hall (Slater) and Terry (Mathis) fight on first meeting, he cleverly yanks her gun out of her holster as she kicks him away. However in the next shot she draws the gun out of the holster.
Factual error: During the scene on the train when Hale arrives in the helicopter, Deakin and Kelly shelter themselves from the incoming fire by hiding behind the walls, and manage to avoid taking any hits. This is odd considering they're sheltering not only behind wood walls, but wooden slats. The M16 with its 5.56mm rounds would easily penetrate the wood, let alone pass through the gaps, and injure, if not kill, our lovely villains. Even if they magically escaped unharmed, there would be bullet holes visible inside the train carriage, but these do not exist when the camera pans through it. Indeed, later on the train, Kelly fires a shotgun which happily penetrates the sides of the carriage. There is no reason an M16 would not be able to.
Factual error: During the shootout on the roof of the train, the antenna is blown to bits. The antenna should be made from fiberglass, but is made from wood...
Continuity mistake: When Terry goes out of the lake, she is soaking wet and without her jacket, and remains without it for several minutes. Then when she hides behind a bush while the truck goes by, the jacket is suddenly back on her.