Continuity mistake: During the lover-husband scene, when the lover and the wife are staring at the husband holding the knife, they keep changing positions from far away to close to each other depending on the shot.
Continuity mistake: The front door of Howard Marks house has no windows on the sides and a rectangular transom window above when seen from outside. When seen from inside, however, there are side windows and the transom window is now an elongated half-circle. Also the house is magically huge inside, and not in a way that suggests a conversion of two houses into a single unit.
Continuity mistake: At the start, when John Anderton is going to arrest the man who can't see well without his glasses, he his trying to figure out which house the killer is in. While looking around, his helmet is fastened tightly around his neck, however, as he is racing off to the house he pulls the helmet off in a way which couldn't have been accomplished with the strap still fastened.
Continuity mistake: When Anderton is in the street escaping on the jet pack the shot from above shows him tilted upwards (so his body looks higher off the ground).In the following shot from in front of him he's much closer to the ground and tilted downwards.
Continuity mistake: When the Pre-crime agents break into Laras house to catch John, they barge in and surround him, when you see the man with the head piece it is fully extended at the time but when the go to place it on his head the headpiece is not extended untill the agent activates it.
Continuity mistake: When Witwer looks at the prevision with Agatha in the mirror it's not broken, but during the murder it is. The prevision was not altered until the time of the murder was altered by John's delay, so the killing was not 'a different one' until after that point, yet the borken mirror error occurs before time runs out, making it an inconsistency with prevision.
Continuity mistake: When Agatha suddenly scares and grabs John Anderton in the pool, she says, "Can you see?" with her right hand over his left shoulder, but when the shot changes immediately, Agatha's hand is now under his left armpit.
Continuity mistake: During the hovercrafts scene, Anderton enters a room where a kid is playing sax. The kid runs away and leans on the wall, but from a back shot he is seen close to the door. He keeps moving between the wall, door frame and aisle, in the rest of the front and back shots.
Continuity mistake: During the lover-wife-husband scene, the lamp on the night table keeps moving all the time: sometimes slightly away from the bed, others a bit of its screen touches the head rest, and in some angles half of the lamp's screen is touching the bed.
Continuity mistake: When we first see the numbers on room 1009, they are all even. Just before Anderton rotates the "6" to its correct position, however, the number is slightly raised.
Continuity mistake: When Anderton and Agatha approach room "1009" (which looks like "1006"), there's a stairwell/exit to the right of the door. When Anderton bust open "1006" and goes back for Agatha, there's now a hallway to the right of "1009."
Continuity mistake: The wooden balls etched with the Perpetrator and Victims show the grain running left-to-right across the names when they are first displayed on the cutting machine. But when Anderton removes the balls and places them on the screen (or drops), the names appear to be written with a pen, and the grain is either non-existent or run top-down across the names. This suggests the balls on display in the cutting machine are nicely generated by a computer and much different to the actual props.
Continuity mistake: When the Precrime team are examining the Precogs in the pool, Fletcher folds his arms. In the next shot he folds his arms again.
Continuity mistake: When Lara, standing, is putting on Lamar's tie while he is seated, he gives himself away regarding the drowning of Anne Lively. Lara's arms stop moving and we see her standing straight, her arms by her side, and she says that she never said that Anne was drowned. We cut back to Lamar, and Lara still has her arms around Lamar.
Continuity mistake: When we see the Leo Crow previsions for the first time, we see the numbers "9" and "6" backwards because we are seeing the previsions from behind the screen. But in the cyberparlor we see the previsions from the same side that Anderton and Riley are watching them, and the numbers are still backward.
Answer: Well, there isn't really a simple solution, but here goes. For a pre-vision to form, there have be two things present within the range of the precog ability (which appears to be limited to the Washington area - regardless of the stated plan to take the programme countrywide, there's never any indication that the precogs can sense beyond that range). Firstly, someone with the intent to kill. Secondly, there has to be a target for that intent within the range of the precogs. Anderton is present, and has the intent within him to kill the man who took his son, but has no target - the real kidnapper is presumably either dead or beyond the precog ability. Burgess, by bribing Crow to pretend to be that man, has provided a viable target for Anderton's intent within the range of the precog ability, thus triggering the prevision, and beginning the chain of events.
Tailkinker ★
The above answers the question, but there do appear to be some time travel issues with this plot point in the movie. Burgess set things up for Crow to fake being the kidnapper and thus triggering Jon's desire to kill that person, everything starts by the pre-cogs seeing the future. If the pre-cogs did not exist or did not have the vision, Jon would have never known that Leo Crow existed and would have continued on without having killed anyone. This is unique within the movie, as the other murders would have been commited regardless of whether or not the pre-cogs saw it. In this case, the ONLY reason this murder occurred is because the pre-cogs saw it.
oldbaldyone
Thinking about this a little more, it could be conceivable that Burgess had planned a different option for Jon finding Crow. We just never saw that on screen, because the precogs changed everything to an alternative future timeline once they saw the original murder. Originally, Jon could have been triggered by Burgess himself, stating that they got a lead on his son's murder and pointing him to Crow.
oldbaldyone
No I think Burgess set it up so that Anderton would find Crow because of the precogs, not have a different plan set up before or else it could be possible Burgess himself would be visible in the prevision. He manipulated the system perfectly, he has done it before after all. He knows exactly how the precogs work so he is able to set it up so that it's untraceable. Except, except for the fact there is always a choice. Only then did it go wrong for him. This proves both true for Anderton and Burgess in the end.
lionhead