This dungeon only has three floors. The exit is on the floor you start on, but you'll need to find a key first. Climb the ladder to B2F, where you can find Map of Bandit Hideout and a hidden room with four Prehistoric Coins (you'll find it if you have gotten the Dowsing Stone). Climb up to B1F and in the last room you'll find the Bandit's Key.
Return to B2F and look around to find some giant holes. Don't jump in any of them. Look for one small hole in one of the rooms and jump down that one to find yourself on B3F in a room with a Cyframe part. Now go back to that locked blue door on this floor and open it with the key. Walk to the exit and voila.
Enemies: Burgessia,
Paldian Lobster,
Death Mushroom,
SaberLynx.
