Having been a fighter controller for 25 years, including at Staxton, that´s the biggest load of coswallop I´ve ever read. Anyone who knows RT terminology would realise that it bears no resemblance to real RT or reality.
IIRC, he was tasked to do a Phase 3 low level VID on the Shak. They surmised he got too low and slow and somehow ended up pancaking into the water. The straps were undone and the canopy unlocked. The surmise was that unstrapped, opened the canopy (the seat was a 90-90 seat) and got out and drifted away,succumbing to the cold. The aircraft then sank and the canopy slowly closed either on the way down or on the bottom.