Indeed, there is magic to this rock-face. And when Ed knocks... the rocks move, forming an opening into the cavern. A 'door' in a fashion.

"Hide the boy. Hide the key. The cheetahs can't know." Al heads into the opening, knowing that his brother will follow him.

People will have to crawl to get through the paths. And once everyone is inside, Al knocks on the wall again. "Close the door. No mud inside."

To Ed's hallucinations, Al is getting older now.