The path of the detonation was shorter than the sound path of the aircraft strike. I'm not saying that the detonation was faster than the speed of sound, although in its first stages it certainly could have been. No, it's about the shorter distance the detonation had to travel.SO what you're saying is the fuel-air detonation reached down to the lobby at faster than the speed of sound of the initial impact? the first man who said he was blasted before the first plane as he was going through the doors into the lobby.
The man could have easily been blasted, and then heard the noise of the approaching jet reflected off nearby skyscrapers. The whole place was full of flat vertical faces, like a bathroom, but large, making it into a sort of giant echo chamber. It is quite apparent in the videos of the approaching plane.
There was a fire after that, definitely above, and probably below. Fires cause other things to explode, like smoke-filled room volumes, sealed pipes and tanks, fire extinguishers and switch boxes. The possibility of other explosions due to fire was so great that one should not attach any particular significance to them.That still doesn't address that there were several explosions after that, which couldn't be related directly to the initial impact. The point is there appear to have been several reports of bombs in the lobby around/before the time of the impact and several afterwards.
You should note you copied my post while I was still struggling for the correct words.