Leaves more questions than answers.
These aircraft normally pull a maximum of about 4G in airshows, the airframe can comfortably handle 7G, that gives quite a wide margin to correct his mistake in turning the top of the loop early.
However, further to the above this was a T7 which was normally fitted with Avon Mk122 engines which I think were the lowest power engines fitted to hunters.
I believe there must have been a degree of blackout, there were fields in the vicinity and he didn't appear to make any attempt to steer, with visual impairment from a blackout he would see the A27 but might not have been able to see traffic on the road.
AAIB bulletin HERE