A quick inspection of the chain shows obvious wear on few of the links, the two biggest groups being one around halfway between Mistletoe's arm and the wall, the other being on the wrap itself. While this thing had no lock on it, undoing the mess created by the captor could take some time. It would probably still be quicker than trying the pulling method.

When it came to the contents of the other cell, the best thing Derrick could find (if he chose to search) was an old plate shattered to three big pieces on a mouldy wooden tray, so nothing that could be of help in this situation. While this was going on, heavy footsteps could be heard approaching the door nearest to their cells.