 FACT: On the aircraft carrier, Darius hooks up the tank to the  catapult and subsequently launches it off of the deck. This would be  impossible, as the catapult would have to be powered up (it is steam  powered), and there are several safeguards in place to keep a single  individual from firing the cat. The catapult has to be set, it is  not just "hot" all of the time, even if steam is available to other  systems on the ship.