He was standing behind a fence. I doubt that his head was much more than a foot and a half higher than the fence posts. The plane wasn't that close to him. It is low flying, but probably the height it is supposed to buzz the ground for radar avoidance.
I was once buzzed by a couple of RAF planes when climbing an Ladder Stile over a Yorkshire Dales wall. I wasn't impressed, but doubt that the plane in the clip was any closer to the soldier than the ones were to me. He (and his video operator) just knew the plane was coming, whaereas I was minding my own business,just out for a hike.
Quack!
GtD.