Skydiving is terrifying enough without the thought that something like this could go wrong - at 12,000ft above the ground.
An Australian guy under the YouTube name Nomadic Adventure uploaded this video, describing it as "possibly the scariest moment of my life".
While working towards stage five of his Accelerated Free Fall programme in November 2014, he had a seizure while attempting a left hand turn.
"Possibly the scariest moment of my life"
He spent the next 30 seconds free-falling, totally unconscious. It was thanks to the skydiving instructor - who came and pulled his ripcord at 4,000ft - that his life was saved.
The man luckily become conscious again at 3,000ft and safely landed he own parachute.
Close call, huh? Just shows how terrifying if something went wrong and you couldn't pull your own ripcord. Props to the instructor for acting quickly!