It seems like a really reckless way to travel. Those things don’t open from the inside. If their driver was somehow incapacitated or if someone were to put a lock on the back latch, the nazis in that uhaul would be in serious jeopardy.
But even without that consideration, the idea of getting into a cramped unventilated vehicle that wasn’t designed for humans and trusting a nazi to transport you anywhere seems ill-advised.