That crash video is hard to watch, all right. I believe it was a smallish company looking to re-engine the Caribou with turboprops, and the pilot was the videographer's son or close relative.
In the piston Caribou, the control lock lever is sensibly positioned in front of the roof-mounted throttles so they can't be advanced very far if it's in the lock position.
In this turbine version, as I recall the story going, the throttles were down on the center console in a more traditional position, and so the protection provided by the control lock failsafe was no longer there. Who knows why he didn't check the controls before takeoff, but it happened, and that's the sad result.