That is an amazing video!
As has been said, the engine suddenly spooling up seems to have nothing to do with relight/auto-ignition. Maybe it's just a result of the impact from the overrun and going into the water. To remember the "fuel shut off" switches as you are heading for the water (or before evacuating) would take a fairly good aviator (as can be gathered from the video, the picture below(?) and the accounts from the accident - this was not the case...)
Some questions and observations come to mind;
Why is one of the women getting out topless(!)?
[pure speculation - I know...]Wouldn't the first "fly-by"/pattern have to be pretty spectacular for the guy to get his camcorder out, run towards the runway and say "we got a nutball trying to land" (or maybe just the fact that any jet was coming in for landing was enough?).
As I was watching the video and saw the paint scheme and the shots of the people getting into the boats I came to think of a picture that someone sent me a while ago (I managed to find it on !!!!!!!!!!!!!!):
http://www.!!!!!!!!!!!!!!/open.file/0171522/M
I had a good laugh when I realized that it IS the same operator!