Revealing mistake: When Howard shoots the subway driver near the end, we see the driver collapse and die. Where did the damage from the bullets go? There's not much in the way of bullet holes or broken glass. Certainly an automatic weapon would've produced some damage.
Visible crew/equipment: After Keanu steals Tuneman's car there is an overhead shot from a helicopter as he's trying to catch up. The shadow cast by the helicopter is visible at the beginning of this shot.
Revealing mistake: When Jack is fighting Howard on top of the train, for a second or two, you can see a blue screen behind Howard instead of the regular background. Someone forgot to add the chroma key background in post. (01:44:05)
Visible crew/equipment: As the bus goes down the freeway, there's a shot of the police chopper following the chase. The movie camera chopper is seen above and to the right of the police chopper that is referred to as a news chopper, but isn't seen again.
Revealing mistake: When Jack and Annie are about to slide out from under the bus, if you look closely when we see Annie hold on to Jack's back, you can see stunt wires visible attached to both characters. (01:29:55)
Continuity mistake: After the first bus explodes, Jack ducks for cover near his Bronco. Soon he looks over at the burning wreck and stands up - but notice that he's still crouched down in very next shot. (00:27:50)
Revealing mistake: When Ortiz first sees Jack stranded beneath the moving bus, he lifts his head to tell Annie. But the pavement, as seen through the bus floor's opening, is completely motionless. (01:17:25)
Continuity mistake: Upon exiting the highway into downtown traffic and blasting through a red light, the bus has a couple of road signs lodged into its bumper which disappear between shots - right before it gets blindsided by a Ford Taurus. (00:47:15)
Revealing mistake: There is a clear shot of Keanu Reeves' stunt double in the Bronco just before it parks on the highway's shoulder near the gridlocked traffic. (00:34:20)
Continuity mistake: The paint that sprays on Payne's face changes splatter pattern throughout the rest of the scenes with Payne. (01:35:30)
Visible crew/equipment: Just after the bus has got on to the empty freeway, there is a long shot of the bus driving off. In this shot, the camera's shadow can be seen to the extreme right of the shot. The shadow is faint, but it is there. (00:51:30)
Continuity mistake: When Payne shoots the train driver in the back, blood appears on his shirt. A few seconds later when he is falling down, his shirt is clean. (01:37:10)
Continuity mistake: When the crane is torn out of the floor and flies towards the ventilation window, from a shot behind, the holes on the base (where the screws used to be) are gone. (00:14:30)
Continuity mistake: In the shots before the bus blows up the Pacific Courier Freight plane, you can see that the vehicle towing it and the plane itself are no longer moving, as opposed to a couple of shots before this where the tow vehicle and plane are moving at a good pace. You also can no longer see the man who is supposed to be driving the tow vehicle (who might have run for it, but there's minimal time).
Continuity mistake: The bus hits a car and wrecks the driver's side indicator. Later on however, the indicator is fixed.
Revealing mistake: At the beginning, when they're talking about "shoot the hostage," the angle of Keanu Reeves is out of focus for a good five seconds. It drifts into focus.
Revealing mistake: In the elevator, Payne grabs Detective Temple by his nose holes, but it's very obvious that Payne is not grabbing his nose and Temple is pushing himself sideways and upwards with his left arm.
Visible crew/equipment: In the scene after the bus gets off the on ramp and hits a bunch of cars, there is a rear facing shot. The shadow of the camera that is attached to the bus is visible during most of the shot.
Continuity mistake: As Jack's initial pursuit of the bus begins, you can see although both vehicles are supposed to be traveling north on the 110 freeway, the sun changes position during filming several times. Shining on all sides for several minutes. This lasts up until the moment that Jack boards the bus.
Continuity mistake: When Jack pulls the Jaguar alongside the bus and starts honking, Tuneman's right hand changes its position between shots. First he's got a grip on the vent window, but then all of a sudden his hand rests on the windshield's upper edge. (00:36:45)
Answer: Ventilation shafts or roof panels.
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