As a skydiver and PP currently in the middle of a heli add-on, scary stuff indeed! You are trained to "always protect your handles when moving about the aircraft" but obviously stuff happens, and obviously could have lost the entire aircraft, although the jumpers might have made it out OK. Scarier for pilots of "cabin class" aircraft as they don't have to wear a pilot emergency chute and so have no chance when the bits by the tail are totaled.
I was on a Twin Otter jump once when a guy's pilot chute got loose on climb out (skydiver climb out at ~12K AGL or so, not aircraft climb out). I saw it go out the door and center punched the guy through the door and out the airplane. Everyone safe although he had a long descent while the rest of us did freefall. I was worried that he was going to think it was all my fault but by the time he got down I had several other eyewitnesses from the load who were very happy with my actions.
Farsouth: the intrepid jumper who did the untangling was unlikely to be in danger if he had fallen, wearing a parachute as he was. The entire load appeared pretty cool and collected as they solved the emergency, including the unfortunate jumper who realized, with the assistance of the intrepid jumper, that the best course was to release the main chute from the harness (there is a release handle for this) and rely on his reserve chute. This is all relative to my perspective as a skydiver, of course!
