I can't comment on the validity of the OP but I will say this. I have heard fire dept. and port authority recordings from 9-11 and the fire dept. was
not expecting a collapse.
About 1/2 hour before first (South) tower collapse one of the incident commanders was growing concerned about building stability
Ordered men out of North Tower, but do to radio problems many did not
hear him
FDNY Assistant Chief Joseph Callan: "Approximately 40 minutes after I arrived in the lobby, I made a decision that the building was no longer safe.
And that was based on the conditions in the lobby, large pieces of plaster falling, all the 20 foot high glass panels on the exterior of the lobby
were breaking. There was obvious movement of the building, and that was the reason on the handy talky I gave the order for all Fire Department units
to leave the north tower."
Callan: "For me to make the decision to take our firefighters out of the building with civilians still in it, that was very tough for me, but I did
that because I did not think the building was safe any longer, and that was just prior to 9:30."
The "two pockets of fire' is often cited by conspiracy types
This was radioed by Battalion chief Orio Palmer from 78th floor skylobby
in south tower
Most of the fire in south Tower was on floors 81-84, nobody made it that
far to report on conditions.
78 floor was sky lobby where people changed elevators - not a lot of
combustibiles as floor was marble lined walls and tile floors surrounded
by elevator machinery
Palmer was giving report on what he saw as made way up - again nobody
made it any farther before building came down