A more complete explanation of the glitch occurs earlier in the video, but he explains the basics of it after he performs the glitch (unfortunately dying in the process). Apparently three different exploiters found three exploits that, when combined, enabled this glitch. Quite fascinating.
http://www.youtube.com/watch?v=7mp0uHr2X6U&t=19m20s
A more complete explanation of the glitch occurs earlier in the video, but he explains the basics of it after he performs the glitch (unfortunately dying in the process). Apparently three different exploiters found three exploits that, when combined, enabled this glitch. Quite fascinating.