Revealing mistake: As Ironbar shoots into the conduit where the kids are, the spots where the spark charges to simulate the bullets hitting are visible.
Revealing mistake: At the start when Max is knocked of his truck, the plane circles and the shot switches to in front of the camels. If you look at the ground you can see the tyre tracks from previous takes.
Revealing mistake: When Savanna first finds Max in the desert studio lighting is seen behind her - this is too low and bright to be light from the moon and can't be light from anything else as they are in the desert miles from anywhere.
Chosen answer: The train tracks would have been covered by dirt for not being used for years. The truck was already cranked, as the engine was source for the generating power and lights. The exit was boarded up and the truck ripped through it. The kids were not prepared, but did observe what the adults were doing and could have been given instructions on what to do.