This as-told-to essay is based on a conversation with 1st Sgt. Micah Symmonds, a US Army jumpmaster in the 11th Airborne Division based in Alaska. It's been edited for length and clarity.

This shocking footage shows the moment skydiver Christopher Jones jumped from a plane only to have a full-blown seizure in freefall! His life was saved by his jumpmaster, who somehow managed to ...