Lever activated door controller. Would open the 'attached' door, which would then close after some time.
Key would have to be in the inventory of the 'mechanic' that attaches the lever to the door.
This would be a way around using an alt charector as a keyring, but only viable as a way to get 'out' of a wall.
The item requirements would be somewhere around the same as the door (pallisade type gear for wooden gates).