Continuity mistake: Stu takes off his wedding ring as soon as he gets in the phone booth. However, in one shot where the camera is panning away from him (just after the police call his "lawyer"), he is wearing his wedding ring again. When the shot pans in, it has disappeared. (00:11:45)
Factual error: The "robot guy" is credited as Nigerian but when Stu pays for the broken doll, he speaks Swahili, mostly spoken in East Africa. (00:23:05 - 01:16:40)
Continuity mistake: In the scene where the pimp starts shaking the phone booth, ad cards and Stu's wedding ring are visible on top of the phone. After the "shaking" the ad cards and ring are gone. A few minutes later the ad cards are back, mixed in with the broken glass. (00:25:15)
Continuity mistake: Towards the beginning of the movie, the Bell Atlantic sticker on the phone receiver is faded, but it eventually turns into a brand new sticker. (00:27:30 - 00:31:15)
Revealing mistake: When Stu is tempting the sniper to see if he will really shoot, the sniper shoots the phone booth, shattering the window, and supposedly hitting or grazing Stu's right ear. When Stu lifts his head, you can see his bloody ear. A few shots later, Stu's head is turned so you can clearly see his fresh wound. If you look closely, you can see Stu's real ear folded back beneath the fake latex one. This happens several more times in the next few minutes of the movie. (00:31:40)
Plot hole: Why wouldn't the police evacuate the area around the booth where an armed (they think) homicidal maniac is making a phone call? All those people would be well within gun range and the city would have been held liable had any of them been shot. Step one is usually to secure the scene for the safety of the public. (00:32:05)
Other mistake: In one scene we see a "chalk outline" on the ground of where the pimp's body was laying. This is something that is never done in real life given it can contaminate the crime scene. (00:34:00)
Other mistake: Several times during the film Captain Ramey's police badge is displayed on his belt and it is a NYPD Detective's badge, not a NYPD Captain's badge. The two badges look very different, so they are easy to tell apart. (00:35:10)
Revealing mistake: At the end of the film when the Pizza Guy is wheeled towards the ambulance and is identified by Stu, you can see the corpse breathing. His neck and chest move slightly. (01:09:25)
Factual error: In one quick shot Stu scans the surrounding buildings looking for the sniper's location. You can see the Grace Building from his point of view. You would not be able to see this building from his location at 53rd. street. The Grace Building is at 42nd & 6th.
Factual error: At the end of the film, the police just let anyone walk around the crime scene: in addition to the caller you also see various tourists gathered around the phone booth. The police would never ever do this: as Leon the pimp was murdered right by the phone booth it is a crime scene and as such must be cordoned off for the forensics team to arrive, instead of letting people contaminate the crime scene. Even though the police "know" the pizza guy did it, they still need to look for forensic evidence.
Factual error: Several times, throughout the movie, Stu or another character using a cell phone is hung-up on. When they are hung-up on, instead of the cell phone dropping, they hear a short dial tone. Actually, when a call is dropped, the cell phone side simply disconnects. You never get a dial tone.
Continuity mistake: Right before the police arrive for the first time, Stu is shot in the ear and reaches up and starts to hold his ear. The camera angle changes to a wide view and both of his hands are now on the shelf in the phone booth.
Continuity mistake: Several times during the movie the police cars forming the perimeter around Stu appear to be closer than they were before. When Captain Ramey first approaches Stu, he has to walk a distance of about half a block. Later in the film he seems to be walking only a few feet.
Factual error: The Caller tells Stu that Channels 2 and 5 were coming to see him. This would be correct, since Channel 2 is the CBS affiliate for New York City, and Channel 5 is the FOX affiliate, but the news vans that show up indicate that channels 5 and 8 are covering the stories. The nearest broadcast Channel 8 is in Connecticut. (The only channel 8 in the New York City area is used by a cable station for a premium channel or local programming.)
Factual error: Right after Stu is shot and the police find the dead pizza guy, Stu's wife runs over and embraces/kisses Stu. Moments later while she is still embracing him, the dead pizza guy is wheeled over on a gurney. No way they would have gotten a gurney up, loaded him on and brought him down that fast. Not to mention moving a dead body from a crime scene without any forensics or investigators doing their thing first.
Revealing mistake: Near the start, in the first few minutes, in several shots you can see barriers that are separating the crowd from the set. They are right back, so they couldn't be too visible.
Continuity mistake: You can see the amount of glass near the cabin changing its size repeatedly during the film.
Continuity mistake: Right before Stu comes clean and confesses his crimes, Kelly gets out of the police car and you can see two police officers in front of her. The camera angle changes to a front view and there is now only one police officer there.
Factual error: The recreation of West 53rd St. is full of mistakes. The street, for example, is mysteriously as wide as an Avenue. The curbs are much higher than they should be, and the buildings are set back much farther from the street than they should be. Studio 54 and the Ed Sullivan Theater should be on the north side of the street, and the back of Roseland should be on the south. There is a subway entrance in the scene that's a block west of where it should be. This is not surprising as the film was shot in Los Angeles, not New York City.
Answer: The pizza man is intended by the Caller to be a decoy so he can get away. The Caller sends the pizza man to the phone booth so that Stu will identify him later in the apartment, giving the police a convenient answer to the mystery while the real Caller escapes. In fact, at the end of the movie, the Caller comes to visit Stu - obviously he's not the dead pizza delivery man.
Phoenix