He was playing music the whole time and had it all lined up on tape. He played Fire by Arthur Brown . My favorite was the Serbian Fight Song used on the 4chan Weapons Board, that was later taken down by ScrewTube. There was nothing random about the music, in fact he may have used the music to time his actions so he could stop at exactly the right time to fire a shotgun three times at his windshield from the inside of his car, with no apparent damage to the windshield. Why? Can you imagine the sound if he was using real shells in that gun? It was staged.