It seems to me that forward speed isn't the problem. I've never flown an Agusta, but I suspect autorotation would entail >1500ft/min rate of descent, which would certainly involve serious injuries to the pendulum on the end of the rope, at a minimum. Never mind the fact that the deceleration in forward speed would likely sling him forward, so the helicopter may land on him at touchdown. It doesn't take much swinging movement to make any contact with a solid object lethal. I've known of skydivers making landings to the water & who were killed because they got too much lateral movement when they overcontrolled the chute near the bottom. I certainly wouldn't want to be either individual in this situation.