The report states he was only 130 lbs under gross max weight at the time of the accident and this was when he was going for a refuel - what was his take-off weight when they started the trip then? Full fuel (110 litres)is just over 200lbs.
130lbs is only 5% below max gross and, adding in the relatively high temperature, he will have been working the aircraft quite hard to get into an OGE hover, let alone then climb vertically.
I wouldn't be surprised if he drooped the Nr trying to lift out of the confined area, slowing down the TR by default and reducing its effectiveness. Then, panic at the prospect of a non-existent TR malfunction led to some serious overcontrolling.
A very inexperienced pilot trying to do things way beyond his capabilities - again!
Shame the TSB muddies the waters by banging on about LTE - this clearly wasn't.