The helicopter dunk tank scenario is not a favorite of the Marines, but still, it saves lives.
In it, Marines mount up into a modified helicopter hull and strap in. Then the hull dunks into the water and rolls over. The Marines have 30 seconds to clear the vehicle.
The simulation is intended to simulate a belly landing in the water, which would result in a roll-over due to the top heavy nature of most helicopters.
The troops undergo extensive training prior to this exercise, and qualified instructors remain onhand.
Still, some Marines can't help but freak out: