Ahem. You can't steal vehicles right out of the factory. Only the buyer can get in the vehicle for the first 30 seconds - and that limit applies to both teammates and enemies. To steal a tank right out of the factory you have to kill the buyer first. Now, if you manage to kill a soldier or whatever class the other person is with your hotwire before said person can jump into their vehicle, then great. But usually that's not a tactic that will work.And besides vehicle stealing, there's not much you can do in the enemy base without heavy weaponry or C4.