Honolulu incident.
Wasn't it shortly after the problems with the double cordite rail that the rocket seat was introduced ? I flew with both the Mk2 and Mk4. seats (Vampire and Hunter). The double charge was always a concern should there be insufficient time to get the seat to the bottom and straighten your back. Seems to have been the case here.
Still at least it saved a life. Rapid and full recovery, Commander.