Continuity mistake: In the shootout scene when they drive away in the car, De Niro is seen in slow motion as he realises there are cops in front of them as well as behind. He raises his weapon and fires, knocking the rear-view mirror off the window. In the shot directly after he is seen still firing his weapon and the mirror falls off the window again.
Continuity mistake: At the very beginning of the scene when Robert De Niro and Al Pacino are in the coffee shop talking about when De Niro was in prison, De Niro's top shirt button is buttoned in the first shot, then it becomes unbuttoned a second later.
Plot hole: In the scene after the bank job where Charlene waves Chris off alerting him of the setup, Chris drives away and is stopped by the cops to verify who he is. He has a fake ID and they let him go. The police CLEARLY know who Chris is and what he looks likes for most of the movie but somehow, those cops don't have anything with Chris' name and face on it?
Continuity mistake: After De Niro beds the woman from the bookstore, he leaves to get her a glass of water. When he returns, there is a different cover on the bed than when he left.
Continuity mistake: While Chris is searching the armored car, Waingro stands there with his gun out. In the background, you can see the spike strip already pulled across the road . A few seconds later, they show the spike strip being pulled out across the road.
Continuity mistake: In the final airport chase, when Pacino and De Niro are at the end of the runway, an airplane lands. It is first filmed nose-on, then the shot switches immediately to a from-behind shot after the plane has passed overhead. The plane in the nose-on shot is a Boeing 747, evidenced by the "bulb" above the cockpit area. The plane in the from-behind shot is definitely NOT a 747 - no bulb.
Continuity mistake: The ambulance that de Niro steals at the start of the film has a red stripe on the sides, but for the remainder of the film there is also a silver 'L'-shaped graphic as well.
Continuity mistake: After the first wave of police cars does the "demolition derby" across the spike strip, they show some cops running out to stop the next group of cars. When they do that, the spike strip is not in the street. Then the scene shifts to a close up of the cop cars skidding to a stop directly in front of the spike strip, which has now re-appeared.
Factual error: In the shootout scene, De Niro loads the injured Kilmer into a stolen Ford wagon, drives backward pushing yet another unoccupied car out of the parking lot. Despite that second car being unoccupied in a parking lot, the car rolls backward (which it can't do in park or with a park brake applied), and after a few car lengths, the pushed car suddenly turns sharply (which doesn't happen with a locked column, which is standard equipment that self-activates when the ignition is shut off). Now, if the car were left running, in neutral, with no brake applied, everything that occurs would be possible. But the combination is very unlikely, especially right behind the car that a fleeing bank robber will choose to steal and ram into it. (01:52:15)
Continuity mistake: When they torch the ambulance, you can see a dealership emblem that says "LEADER" right above the Chevrolet emblem on the back door of the ambulance. It is visible right after Chris puts the bomb in. In all other shots with the ambulance, this emblem isn't there. Obviously the "LEADER" ambulance is a "fake" that they used just to burn and destroy.
Continuity mistake: In the shoot-out after the bank heist, Vincent's rifle starts out as an AR-15 style with a carry-handle, but by the time he catches up to Mike, it switches types and has no carry-handle.
Continuity mistake: When Neil talks to Chris about Chris' marriage, Neil's hand holding his coffee cup moves up and down between shots. (00:39:25)
Continuity mistake: When the crew's black van is in front of IGM, Trejo turns the parking lights off and there's a shot of Neil coming out the door to hide in the corner. Then they switch to the police monitor where Vincent is watching Neil, and it shows the van's lights are still on.
Factual error: When Vincent enters the nightclub, you can see that a woman is walking through the metal detector, but the security guard is scanning her with a hand-held wand at the same time. This is totally unnecessary. The hand-held should be used only if the walk-through is triggered. (00:43:50)
Continuity mistake: The armored car robbery takes place in the early morning. Waingrow pulling on his clothes, the light in the sky all say early day. By the time Pacino arrives to survey the scene it's pitch black and all the bodies are still on the ground.
Continuity mistake: In the scene when De Niro kicks down Waingrow's hotel door, on the police TV you see the sign on the door handle fall off. However when De Niro enters and hits Waingro in the face, the sign is back on the handle. (02:33:50)
Other mistake: In one scene, Vincent asks one of his subordinates how he is after getting shot. The reply is "Banged up, but I'll live," but the subtitle reads "Hang up, I'll live." (02:06:50)
Factual error: At the end of the movie, Pacino is chasing De Niro amongst the Navigational Aids at the airport. As a jet approaches, the approach lights are turned up to full brightness. Full bright is only used during decreased visibility (not the case in this scene).
Continuity mistake: In the armoured car robbery, when the explosive charge is fired, the windshields of the row of nearby cars all explode outward toward the blast instead of inward away from the blast.
Continuity mistake: In the parking lot, when Waingro escapes being executed, Neil and his crew spread out and look for him. It is nighttime and the sky is clear. Yet when Neil looks out to the distance, it is raining in the last shot.
Answer: Waingro helped Van Zandt track down Trejo. Waingro then tortured Trejo and threatened his family if he didn't give up McCauley. With his back to the wall, Trejo gave Waingro and Hugh Benny the details of the bank heist, but Waingro killed Trejo's family anyway and beat Trejo almost to death. Benny then gives the tip to the police on Van Zandt's order.
BaconIsMyBFF
I wonder how Trejo was tracked, I don't remember his name being revealed during Waingro's time with the crew, or any other information.
Well, we never see the crew prior to their first heist. Trejo could have given Waingro his name during the planning of that heist.
BaconIsMyBFF
Waingro met this crew only once. How would he know who Trejo is or where he lives? Right before the heist, Trejo is asked to mislead police away from the heist.