In the scene when they are running from the raptors in the visitors center, they climb out of the ceiling after coming from the control room and jump onto the T-Rex skeleton. After they manuever around while getting away from the raptor as the ceiling weakens, the first one to fall is the young girl. As you watch her piece come apart from the ceiling, watch closely. You will see her piece fall, and then they cut to a different angle and show her fall again. Nice editing, people.