At the crane part, you are supposed to progress to the bottom-left and go up the elevator. Then, on the floor with the holes, carefully walk from the left side of the room to the right and do not fall down any holes. Fight a trainer then go up the elevator on the right side of the room. After going up that elevator, go left then up until Snattle arrives for a battle. (That rhymes

) Then the elevator that he came on will be unlocked after you beat him. It takes you back to the beginning, but you can leave and come back and it will let you go back up.