From the best I could see he either had a VERY VERY small pinhole leak coming from his secondary fuel rail near the #1 rotor's secondary injector or a faulty lower intake mani to block seal that would only leak under 18psi-ish+ of boost.
During a hard pull, fuel mist would escape, and as soon as he let off, BOOM.. we have ignition. I still don't know what ignited the fire(s).
I PM'd the guy on rx7club and he made it home to West Virginia fine.