He sounded pretty calm and collected to me for a man who was watching his and others lives flash before his eyes.
He didn't know what had happened, about the planes.... he thought it was just a fire. His "oh god" at the very end wasn't very calm, that's for sure. How could anyone possibly wrap their minds around it?
Nobody expected both towers to collapse. Watching the second one fall on tv was like seeing a horrible movie. It just didn't seem real.