12,000 ft sky dive goes horribly wrong when sky diver begins to suffer convulsions half way down the jump

Christopher is a sky diver who will never forget this near death experience when his started suffering convulsions half way down a routine sky dive jump.  Luckily, he was diving with a jump-master who notices something strange, and manages to pull the ripcord around 4000ft and deploy his parachute safely.  Christopher later regained consciousness and was able to land safely back on the ground.