It was actually another Hiller. Same thing happened when a very brave A&P climbed out and pulled the collective lever to flat pitch. The resulting change from full power climb to sudden descent caused him to loose his grip and fall. The control loads then sent the collective to the full stops and KB (the pilot) could only push forward and aim for a runway a couple of miles ahead.
With no way to reduce power with out loosing rotor rpm he quickly excedded vne and landed on the l skids at about 120 mph. He was then able to roll off the twist grip and shut down. If I remember correctly the helicopter skidded about 1000 yards. Very sad day. We named our new company address in memory our boy.