Word is from others that were there, the fighters and the bombers were running a pair of rat race tracks, with the fighters inside the bomber loop. The P-63 was third in line and may have simply lost position due to the "crack the whip" effect that can happen in tail chases. One video may be evidence of him pancaking into Texas Raiders.
It was hard for me to watch as I have friends and acquaintances in both the B-17 and P-39/63 community along with the B-29 and Tora group, and no knowledge of who all were in town this weekend.
Craig