Thats not surprising ref the seat becoming entangled. An ejection with an IP/student a course ahead of me in Moose Jaw (around 1997-8) ended up with exactly the same results. It was determined that the only reason student was able to survive was that he had been an extremely experienced airborne soldier prior to cross training to pilot and was able to manually disentangle the seat from the risers/parachute. He fractured his spine and spent a couple years recovering before he was able to resume training. The fact of the matter is that this seat has been plagued with issues for decades -it doesnt really have an effective seat-man separation mechanism other than a band aid solution that was put in a couple years ago.