>> i couldn't quite work out what the problem was. >> the bikers are on their ninth lap around the track when kirkham loses control. >> from my position, i could see them coming under a bridge just around a bend. >> oh! >> saw one bike just slide and starts heading what i thought was to my left-hand side. >> it was kirkham -- >> kirkham and the bike fly across the track and slid into the grass. >> i thought, this isn't too bad, i'm not going to hit the barrier, i'm just going to slide across the grass and stop. but i didn't miss the barrier. >> kirkham is knocked unconscious, but his 363-pound bike continues toward smith and his camera. >> there was no fear time of the actual crash. it all happened so fast. >> the bike moved so quickly and with such force, it's hard to tell how smith survives the impact. but a closer look at the video shot from another camera across the track reveals what happens in the critical seconds of the