During the battle of Helms Deep, when the Urak-hai start using those massive ladders which are lifted by ropes connecting to the walls of Helms Deep, you see one ladder lose its connection to the fort and fall back to the ground, crushing numerous Urak-hai. But before this happens, we see the same ladder in a far shot being holsted up, it was on its downward decent about to make contact with the wall. I'm certain that even if the ropes were shot out, it still would've fallen onto the wall and not back onto the Urak-hai.