Revealing mistake: When Michael Douglas attempts to swing on a vine over a deep abyss, the rock that he runs into on the other side moves like a marshmallow, indicating that it's a fake rock. (00:39:10)
Revealing mistake: It's quite visible that the vine Jack uses to cross the gorge is a rope. (00:39:25)
Revealing mistake: When Joan is about to get in the bus at the airport, there's a man in a red shirt walking from right to left who can't help staring at the camera and grinning all the time. (00:19:25)
Revealing mistake: When Jack drives through the field to reach the cave, tyre tracks are already in the grass, showing it was not the first time the scene was shot. (01:15:40)
Revealing mistake: When Jack and Joan's car goes into the river, a rope is visible holding the car to prevent it from flipping over. (01:21:10)
Chosen answer: She's lost in Columbia and doesn't have access to money beyond what she has with her. She doesn't want to give him everything she has because she doesn't know when she'll be able to get more.