Bowman, John

Aus 9/11 Wiki

John Bowman, a retired Marine lieutenant colonel and a contractor, was in his office 
in Corridor Two near the main entrance to the south parking lot. "Everything was calm," 
Bowman said. "Most people knew it was a bomb. Everyone evacuated smartly. We have a 
good sprinkling of military people who have been shot at." 

He was inside the building and did not see the flight of the aircraft. He actually thought it was a "bomb".

Source List: Bart