So this is the first quadcopter flight I did with my Gopro attached. Unfortunately it was also my first crash.
After cruising around in stabilised mode for a while I decided to give stunt mode a go, and got all out of shape then panicked and crashed. Stupid. Unfortunately the Gopro wasn't even in its case so it went flying. The battery fell out. The SD card fell out. This is why the video has no sound, and cuts off abruptly - that's all I could rescue from the card.
Still, very pretty. Can't wait to FPV this thing - it will be like flying!