I had a buddy in the 82nd. He told me there are a couple of things that can happen when you jump. Sometimes if you pack your bag incorrectly it'll fail to deploy and the device that pulls your 'chute out of the bag will snag within the bag. He told another story about how if your "slack line" wasn't just perfect with tension, your parachute won't deploy. The final horror story he told me was if your line was fouled, it would get wrapped around your rucksack as you jumped and either tear you free of your bag, or instead it'll hold and you'll end up twisting in the wind.

the story he told me was before the time they had a retrieval device in the airplane. Some poor sap jumped out of the plane and his slackline wasn't under the proper tension.. Apparently he slapped the side of the airplane for 200 miles of travel as they tried to get clearance for an emergency landing. Apparently he landed like a bag of soup and just about every bone in his body was broken...

your guess is as good as mine, but it sincerely looks like he got the slackline wrapped around his rucksack to me.