When I built my cabin I naturally thought about trap doors, tunnels, false walls...
Yeah...no. Not a lot of room for false walls in a 12X16 structure, and to trench far enough in the rocky ground for a useful tunnel...well, that wasn't a pleasant prospect. Easy to come up with excuses reasons not to.
But when I figured out that the wood stove would have to stand right next to the stairs to the sleeping loft, well, that didn't seem like a good idea, either. If anything caught fire during the night, I'd have few alternatives to sitting there and sizzling. Not acceptable. So I'm building a kick-out hatch over the front porch roof, in the back wall of a closet. Won't be much help if the MZBs come calling, but it'll work for escape in case of fire or similar emergency. I plan to stucco over it on the outside, so it won't show from the outside.