When Merry and Pippin have been taken by the orcs and the uruk-hai and the two groups start fighting, Merry and Pippin try to get away, but with great difficulty as their hands are bound. When Eomer's men arrive and start taking out the orcs and uruk-hai one of the horses buckles and we see a shot of Pippin looking up toward the horse(camera) with his hands free! Then when he quickly moves out of the way, his hands are tied again!