To get a creature through a wall to the other side without tunneling an entrance and leaving yourself open to attack, possess a level8+ Warlock, or any other creature that possesses the whirlwind spell, and move to the corner of a room that is missing a corner block. (Just two blocks diagonally touching). Line up the creature you want to blast through with the crack in the corner, and cast the whirlwind spell. If done correctly, the creature should pass right through to the other side. Ready to explore the outer caverns.