His lever spontaneously leaped from his grasp, delivered a glancing blow to the side of his head, and disappeared in a sudden cave-in. The sharp blow sent him reeling. A flying stone from the rockslide struck him in the back and he fell gasping, uncertain whether or not he was falling into the pit until the instant his belly hit solid ground and he hugged it. The roar of the rockfall was deafening but brief.