This is video by Doctor Mark Heath just before the building collapsed on him. We can excuse it's jerkyness.
A more common version of this video doesn't start so soon, but goes longer and has his plaintive "I hope I live".
Doctor.wmv

The entire heart-rending plaintive video is available at:

http://www.boredom.org/video/markheath.mpg

http://www.loftninjas.org/projects/20010911/videos/cnn-asf-
20010911/amateurvideoafflmed.as

"While the news footage of the collapses showed the facts, amateur video has shown the reality of what it was like to be there. After Dr. Mark Heath heard the first airplane explosions, he ventured toward the site to offer assistance, camcorder in hand and recording. He was asking a bystander where medical assistance might be needed when a noise above tempted the camcorder upward. As an enormous cloud of gray dust and debris descended, all Dr. Heath and the people around him could do was run until the cloud engulfed their position. Heath, constantly narrating for what sounded as if it might be posterity, described how broad daylight had turned to complete darkness"