In the scene where Christian enters the train door and Dr. Cecil points one kind of gun at him, then a second later it is a different kind and a second later back to the first one.
When Christian enters the mine he leaves his pack on a rock then investigates further and discovers that he has to swim in under ground tunnel. When he dives down he's not wearing the pack and when he comes up on the other side hes wearing it.
As Christian Erickson slides after his motor cycle lands on the train, he can be seen rolling on a wheeled platform.
The reflection of a crew member can be seen in a window as Christian Erickson looks around a room.