How does an elevator car explain the numerous explosions reported at different levels long after the impacts? It doesn’t appear possible that the relatively low temperatures in the core caused a continuous/steady stream of falling elevator cars.
There was also no failure of structural elements (like the crane example) prior to the failure at the collapse zone. Others believe the explosions were a natural result of the fire (even lower down the building where there was no fire), though the FDNY and FBI both believed on that morning there were “secondary devices” planted in the buildings.
So shocked were the FDNY by the first complete collapse (rather than partial collapse after a number of hours as their experience suggested), that a discussion immediately followed in their ranks as to whether the building was brought down by charges.
Of course their initial determination and subsequent theory were correct.