[Although John suspected that he certainly wouldn't notice anything if Sherlock didn't, he still investigated the shack as well. Periodically he'd tap on suspicious-looking dark splotches in the wood, wondering idly if it would reveal a secret door. But to no avail. He put his hands on his hips.]

Unless our perpetrator's a particularly evil rabbit and can just tunnel in, I'm not seeing how you get in or out of this thing.