I was a student on ULAS at the time, I’d watched the F16 do its stuff from my car while waiting at the lights to cross the runway then driven to the Mess for the beer call. I was walking from the car park when the F4 practice started & thought he seemed rather low in his loop. From my line of sight he disappeared behind some buildings then there was a big fireball. It was rather shocking to witness as a student pilot & even more so when I discovered that bits of wreckage had taken out the fence line where I’d be parked only a few minutes before.