i think your plane survived because after a split second of the canopy departing the main hatch blew off from the pressure build up within the fuselage. a plane without a weak link like a big hatch may not fair so well and the pressure build up may get the better of it. i have seen a few planes "blow up" in flight like this.

but i am in no way implying this happend to the UB, i was not there and did not see it so cant comment.

Dave Stephens