sort of tri pod it through that area. >> he makes it, but barely now it's miles' turn. he tries the same technique, but loses his balance. suddenly disaster. >> oh, [ muted ] oh, my. >> you see him fall for a while. you see him hit and bounce. he catches more air, going shoulder over shoulder. i thought i was watching miles fall to his death. >> after miles plummets almost 150 feet over jagged rocks, his friends see him leap to his feet. >> are you all right? >> sit down, sit down. >> make sure you know everything is connected. >> miles scrambles back up the stony slope. he can't believe he's not more badly hurt. >> i was wearing a helmet and a backpack, both of which i credit with saving my life.