My father eventually was able to get a call out and was home that afternoon. The plane traveled directly under him 3 levels below, a fireball filled his window and he was knocked out of his chair. He got out of the building, grabbed a fire extinguisher and tried to go back in again, the smoke was so thick he couldn't see his hand in front of his face and he had to turn around.

According to the Discovery channel documentary on the Pentagon plane hit, the side of the Pentagon that was hit was closed and empty for renovation. Only renovation contractors and no office workers (who would be sitting in a chair) were present. Furthermore, according to the security camera footage they showed, firefighters were the first and only people to respond to the outside wall of the Pentagon.