We used to do this spin/decent show-off maneuver in the AS350 during heliskiing sometimes,
but usually not that steep of a nose down attitude like in the video, no need for that. Kept speed at 60-80 kts 60-70° bank with nose probably 45°down and with 40-50% Torque to maintain Mr rpm
It drops like a piano in that attitude, faster than in auto and you would like to have some 2000 feet below you at least
And for sure your are killing the MR frequency dampers if you do all the time.
But the clip looks legit, not like some green screen fake and that waterfall looks like at least 1500 feet drop so Tom had good ground clearance when he comes of it.