Tim was skydiving with his friends back in 2007 when his parachute got tangled and he came falling down to earth (@ 2:24). The fall broke his pelvis, back, and neck. Making him instantly paralyzed.
In the video’s description, he states:
I awake days later after surgery and begin life as a quadriplegic. It’s taken me four and a half years to be able to watch this video.
The fact that the camera taping the accident was fixed on Tim’s helmet himself makes us see what happened just like he saw it. I can’t imagine the thoughts going through his head during the whole thing.