Once you drop down Ladder A, the Mt Moon B1F and B2F layout functions as a series of interconnected tunnels rather than an open cave. The first B1F room is merely an isolated transitional catwalk. Run directly along the short elevated plank to Ladder B, which descends straight to the western edge of B2F.
The second basement floor houses the narrative core of the mountain. Here, members of Team Rocket are actively poaching prehistoric specimens. As you move along the northern edge of B2F, you will trigger an unavoidable confrontation with a Team Rocket Grunt fielding a Level 11 Sandshrew and a Level 11 Rattata. Running a Squirtle or a boosted Mankey neutralizes both in three turns flat.
Follow the cavern southward around the rocky ridge. In a dead-end pocket just south of this Grunt, you will spot an item ball containing TM46 Thief. In speedrun categories, this Dark-type move is occasionally grabbed to strip held items from wild Pokémon later on, but pure speed routes bypass the nook entirely to preserve split times. Round the southern corner and sprint north toward the cavern's center stage.
