Continuity mistake: In the exterior shot of Sal entering the bank, there is a car parked by the door. In the interior shot, the car is not visible behind Sal. This mistake is reversed half a minute later when Sonny enters the bank. There is no car in the exterior shot, but it can be seen in the interior one. (00:04:00)
Dog Day Afternoon (1975)
Ending / spoiler
Directed by: Sidney Lumet
Starring: Al Pacino, Carol Kane, John Cazale, Penelope Allen, Beulah Garrick, Sully Boyar
Sal and the hostages are taken to the airport in a car and as there about to go to the plane, the driver gets a hidden gun, shoots Sal in the head and Sonny is arrested. All the hostages are free and Sal is lead off on a gurney while the police read Sonny his rights. Sonny goes to federal prison for 20 years. Leon gets the sex change operation. Angela (Sonny's wife) and her children live on welfare.
Kruger-Brent
More mistakes in Dog Day Afternoon
Sonny: You! Manager! Fucker! Don't get any ideas, you hear?
Sheldon: Believe me, I'm on your side on this one.
Sonny: Yeah, my side, shit.
Sylvia: Look, there are young ladies, here. You could watch your language, you know.
Sonny: I speak what I feel. "Watch my language." Empty the drawer out.
Question: What would've happened if Sonny drove the limo himself, refused to tell the police where they were going, and told the police not to follow them? Also, if Sal had hostages sitting behind him as well, making it impossible for the police to get a clean shot? How could the police have stopped them, without getting any hostages killed?