Continuity mistake: When Annie swerves to avoid the schoolteacher and the kids, in the previous shot of the kids and the schoolteacher, they have already stepped out onto the road and are crossing, yet when the camera cuts to a view looking out the bus the schoolteacher and the kids are just stepping off the curb and walking across. (00:48:50)
Continuity mistake: When McMahon is in a helicopter trying to guide the bus from downtown traffic onto a vacant freeway, the bus passes through the same neighborhood twice from one overhead shot to the next, roughly one minute later (pay attention to the recurring trio of flagpoles on the right, as well as a pair of cars that the bus overtakes). (00:48:55 - 00:49:45)
Visible crew/equipment: After the bus exits the freeway, as it drives on the city's streets the forward looking street-level action camera is visible, mounted behind the tire. (00:49:05)
Continuity mistake: When Jack is on the bus and is coming up to the construction site, if you look out of the bus to the left the scenery changes, from having grass on the left before the construction site, to having dirt between shots. (00:49:30)
Visible crew/equipment: When McMahon is giving Jack directions to the vacant 105 freeway, a well-dressed crew member wearing sunglasses and a big grin is visible sitting in the aisle of the bus. (00:49:50)
Continuity mistake: An obvious stunt double is briefly visible pushing a baby carriage full of cans into the crosswalk as Annie unknowingly rams the bus into it. Initially we see an older woman pushing the carriage along after chatting with her friend. In a view from within the moving bus's front window, however, a much younger woman has briefly taken her place for a couple of shots. (00:50:05)
Visible crew/equipment: During the scene where the bus takes the really sharp curve it kind of goes over on two wheels - if you look closely, you can see some sort of lift under the bus obviously causing it to tilt so far sideways. (00:50:10)
Other mistake: The bus is supposed to maintain a speed higher than 50 mph to avoid disaster. But at one point where the baby carriage full of cans falls to the pavement and starts tumbling we can see part of the bus in the background, slowed to a crawl and certainly not traveling at least 50 mph. (00:50:20)
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)
Visible crew/equipment: After Lieutenant McMahon requests to be flown to the 105 freeway interchange, a camera operator can be seen standing beside an overpass column when the bus and police escort drive by. (00:52:50)
Revealing mistake: In the scene after the bus makes the hard right turn, it's moving towards the exit onto the 105 freeway. The bus is surrounded by cop cars and motorcycles - the camera angle is from the air. The bus slams on the brakes to avoid hitting the cop car in front of it - it's only a second but it's obvious the bus wasn't going over 50mph. (00:52:57)
Visible crew/equipment: A camera crane is visible in the bus's rear window reflection just as it enters the empty 105 freeway via police escort. (00:53:35)
Visible crew/equipment: As Harry walks out of the office after telling his colleagues to search for their mystery bomber via pension fund files, a boom mic pole is reflected in the left window when he says, "I've seen this a**hole." (00:55:25)
Continuity mistake: Just after the bus driver has been unloaded and Helen tries to get off, Annie shouts "No Helen" at which point Jack turns around and grabs her shoulder to stop her. The shot switches to Dennis Hopper watching TV and then back to the bus where Jack is no longer even close to Helen when the bomb detonates. (00:56:45)
Continuity mistake: In the shot where Payne gives Jack permission to unload Sam from the bus, listen closely to the male news anchor on the immediate right. He reassures his viewing audience that the bus hasn't exploded, although a woman was caught in the blast and fell. This report airs roughly two minutes before the incident even takes place. (00:57:05 - 00:59:15)
Audio problem: When Sam is being loaded onto the trailer, Jack's mouth is visibly closed when we hear him say, "You got him? You got him?" (00:58:30)
Revealing mistake: If you look at the missing part of the bridge, and look at the shadow underneath, the shadow is of a full bridge. (01:02:35)
Continuity mistake: When Norwood and McMahon break out their maps after hearing about the gap, their platform truck passes a large overhead freeway sign on the right, as seen in a rear window reflection. But a second later, when McMahon insists that the freeway is finished, the sign is roughly 100 yards away instead. (01:02:40)
Revealing mistake: In the scene before they jump the gap, they played the film in fast forward to make the bus appear to be going faster. If you watch the police on the truck in the background, they are moving in fast forward as well. (01:02:50)
Continuity mistake: Shortly before the bus gap you can see an END sign at the end of the road. This disappears a second later. (01:03:11 - 01:03:36)
Answer: Ventilation shafts or roof panels.
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