As the aircraft gets abeam of the guy filming, there is a puff of dirt from the tail wheel as it comes off the ground and back down. Is he off the side of the runway at that point?
Also, there is no deflection in the elevators at that point. I realize they are drooping in the post fire pictures.
Has there been any publication or interview with the guy filming. He sees something early in the take off and seems to know something is wrong.