After the attack on the tour vehicles, when Ellie and Muldoon go out to the cars in the jeep, they rescue Malcolm then Eille sees the wrecked car and goes to it. During this, Malcolm says "That's an impact tremor." If you look, the second tour car is next to him and the road is concrete, but when he hurries them to get in the jeep, the tour car is gone and the road has turned to mud. Another point is right at the beginning where the vehicles first go to the T-Rex paddock they are heading east and they appear through a tunnel. Then, back at the scene where Malcolm says to himself "That's an impact tremor", the jeep is facing the same way as the tour vehicles. Because the tour vehicles are returning, they are heading west, but now when they are all in the car driving away from the T-Rex, they don't drive through a tunnel. Where has it gone?!