Continuity mistake: At the very beginning, when you see the English family on the beach, the little girl wanders off and you then see a shot of her on her own. However, she must have walked a pretty long way because the beach she is on is definitely not the beach that her parents were on; the rocks in the ocean are gone and the waves are smaller. (00:02:00)
Continuity mistake: When Rowland and the other man spot the baby T-rex, it is eating its meal. Then it looks up at them. Then it cuts to another shot where Rowland and the other man are talking. If you look in the background you can see the baby with his head down eating again. Then it cuts back to where the baby is. It is looking up at them again. (00:39:30)
Continuity mistake: When Sarah gets those cuts on her head, they seem to dissappear or get smaller in number as the movie progresses. (01:03:15 - 01:18:05)
Deliberate mistake: When Sarah, Ian and Nick are climbing up the cliff with the rope, Sarah is able to easily pull the rope up to place her hand underneath it for a better grip. The rope is quite lax for having three full-grown adults hanging from it.
Continuity mistake: When Sarah, Malcom and his daughter argue in the trailer for the first time you can see out of the back window. It shows they are right in front of a thicket of trees a few feet behind the trailer. When they step outside a minute later to see the InGen choppers arrive you see that the trailer is pulled up on the cliff tops already. The only view you should have seen out of that window was open sky as the window points out to sea. (00:32:10)
Visible crew/equipment: When Sarah is returning the baby T-rex to the parent dinos, just as she is about to release the baby so it can "walk" back to its parents, look at the bottom of the screen. You can see someone's head pop up for a second, presumably a crew member taking the animatronic baby from Sarah. (00:55:55)
Continuity mistake: The cracks in the rear window of the lab truck when it's hanging over the side of the cliff seem to vary between the shots outside underneath vs shots inside as to where they are in the glass. There is a major one above (not underneath) Sarah's hand that's visible from inside and not from underneath.
Visible crew/equipment: In the scene in the shed towards the end, when Kelly does her gymnastics, you can see that it is a stunt double.
Continuity mistake: Towards the beginning where the girl goes to photograph the Stegosaurus, the scene cuts back to her boyfriend and the guy with the video camera. In two cuts to their scene while the girl is photographing and interacting with Stegosaurus, the guy with the video camera opens the flip out LCD on the video camera and starts shooting the action. (00:24:50)
Visible crew/equipment: When the two T-rex's surround Eddie's car one bites the roof off if you look to the right side of the roof once in the T-rex's mouth you will see a large wire obviously so the model and the roof don't fall over.
Continuity mistake: When the girl holds the sandwich, the napkin around it changes size and position between shots. (00:02:20)
Continuity mistake: When the movie starts and the little girl is surrounded by mini dinosaurs, her father lowers his Financial Times newspaper twice. First in the closeup he lowers it to his lap, and then at the start of the next wideshot the newspaper is back up in front of his face when he lowers it again before it drops onto the sand. (00:02:40)
Revealing mistake: When the dinosaurs are released from their cages and are running around the camp, a jeep is launched into the air and lands almost on top of the 2 hunters who leap from the tree. When the jeep falls forward, and down out of the tree the bottom of the tree moves and shakes in a way it shouldn't if it was truly made of wood.
Other mistake: When the velociraptor jumps for Ian, it hits an electric panel and shorts it out (the red lights go off). In the aerial shot of Kelly's acrobatics the panel lights are on and the raptor is gone. When it jumps from the ground to the catwalk the lights are off again. Then on again when Ian and Kelly run from the shed. (01:36:00 - 01:36:48)
Continuity mistake: When Sarah looks up at her jacket, the bag of snacks is on the opposite side of Kelly. The bag is closed and the chocolate bars are unopened. Also, there are no crumbs between the two characters. But as the T-Rex is approaching, Sarah is gathering the now opened snacks and dusting crumbs off the top of their sleeping bag that was not there in the overhead shot. (01:21:29)
Continuity mistake: As the camera pans from Ian to the tent, Sarah, the lantern is out and the front flaps are open/tied back. From the interior shots, that lantern is still lit and the flaps are hanging loose. (01:21:39 - 01:22:07)
Continuity mistake: When the crew are looking for Sarah, Eddie is holding the tracker and Ian is holding the rifle. In the next wide shot where they watch the Stegosaurus cross the river Eddie is now holding the rifle and Ian the tracker and the bag. The scene cuts again to the close up and Eddie is again holding the tracker. (00:22:00)
Revealing mistake: As the T-Rex rages through the street, some cars crash, and one reversing car dramatically flips. Two problems though - firstly, it's reversing quickly enough to mean it must have travelled past the dinosaur to build up that much speed, so the driver would have just driven forwards away from the T-Rex instead. Plus there's nothing which would realistically be in the road to make the car flip over like that, it's just a street with cars stopped on it.
Revealing mistake: The woman who screams and reverses away from the T-Rex while staring at it is suddenly replaced by a male stunt driver looking over his shoulder in the shot from the side.
Visible crew/equipment: When Ian and Sarah (with the baby T-Rex) are pulling into the gas station, if you look in the rear view mirror, you can see the heads of a number of crew members watching. (01:53:47)
Answer: Just after she makes the statement, Ian sees the T-Rex outside of the van window and realises that it is going to attack them regardless of the fact that they've returned the baby Rex.