Marty, no offense but remember that I'm pretty experienced with what happens in various scenarios as both a safety researcher and someone trained to recognize the mechanisms of fire from my time as a fire department officer.The operator said he noticed a fuel odor when entering the plane over a 3 week period prior to the accident. One day he got in, turned on the master switch which made a tiny spark, the one in a million odds that the fuel air ratio would be perfect hit jackpot and BOOM! There he was sitting in the seat, plane disintegrated around him, hand still on the master switch, saying "What the........?"
What you're describing doesn't match that photograph in the slightest nor is it really compatible with survival for a couple of reasons. Inhalation of superheated gases associated with a flash fire or the thermal effects from a fire large enough to create the over pressure to blow apart aeronautical structure are both going make it so that someone is going to be critically injured or rapidly dead and not sitting there wondering what the hell just happened.
I think you were misinformed. The risk you're describing is real- albeit extremely small- but that aircraft would have burned like a funeral pyre in the scenario you describe. It looks like a collision of some sort, mostly like on the ground with a larger aircraft or a building. I can't read the tail number but if you can figure it out, it would certainly settle the question of what really happened.