In 2007, the British Airborne trained with the American Airborne and jumped together. Two paratroopers, one American and the other British (cameraman), became tangled at 1200 feet and thus fell earthward together until the last 100 feet when they managed to untangle and separate from each other at the very last minute. A nice laugh followed...
The American paratrooper is not "freaking-out". He is moving his legs like that (running in place) because that is exactly what you are trained to do when you become entangled. On my first several jumps in the Army, I made it a habit to run in place after my canopy opened so that it wouldn't slip my mind in an emergency (there is a thousand things going through your mind during a jump, at least until you get used to it).
AIRBORNE!