FWIW, if you have done any video encoding, one of the really annoying things is sometimes the video and audio get out of synch, with the audio usually lagging. I've had this happen many many times. That could easily be the explination of the problem with that video. Some of the other points, such as an apparent lack of arterial bleeding from the cuts are harder to explain.
JNo, not encoding, you have to see the video, there is maybe a 5 second lapse between the actual cutting and the screaming, plus all the other actions are in synch with the sounds with maybe 1/4 of a second lapse if any