First, copy the roller guy with Axl. After you get past the elevator with the armor opponent, there are two elevators. Keep on the left elevator for two seconds then jump off. Get out of your Ride Armor and at the bottom there is a small hole. Use the ability from the roller guy and go through the hole to get a Rare Metal. Then, keep the Ride Armor and have a Prickle Barrier . Go through the spike floor and the elevator will move. You can now get another Rare Metal.