I have not looked closely at how the bottom is held in to Dredd. If it is slipped in to a slot in the bottom of the cab, something happened to cause it to slip out. The sides spread, the bottom flexed, etc. If you look under the cab and do not see any broken pieces of wood and there is a groove for the bottom, see if you can get it to slip back in to place. If it does, you should be able to secure it by attaching a few small blocks of wood along each side under the bottom and screwing them in to the side of the cab. If the cab is not stable or is twisted, you will need to fix those issues first.