Bronx
If the chute had opened then there would have been no accident and hence no SI. Longstanding mil occurrence categorisation holds that an "accident" involves major injury (broadly, broken limb or worse) or Cat 4 damage to aircraft. If Sean had walked away then this would have been merely an "incident" and subject to nothing more than a unit inquiry, which would not be released by default (although FOI would probably see it released if someone asked the right question).