Hall of Infinite Doors

On our first step into the door, you lose your balance and fall into a huge slide leading you hundreds of feet underground. When you reach the room at the bottom, you see a vast area the size of a football field, lit dimly with flickering lights. Straight ahead of you is another door all the way across. Moving across the floor at very high speeds are what look like car sized boulders. You look to the right and see a note stuck to the hallway wall just inside the door. It reads:Your goal is to get all the way across to the other door without being flattened by a boulder. Without a second thought, you sprint full speed into the room. He vaguely hears a soft song in the background that he recognizes as the Rolling Stones.