mm43 - with regards to burning off 476 knots, at about 1 g acceleration that takes about 25 seconds. At a little under half a g it takes a minute. Maybe that will help thinking processes a little.
Burning it off is possible. But the location where the plane seems to have gone down would require God step in and swat the plane out of the air with a multi-g deceleration.
So was the plane trying to turn back for some reason? Without the CVR it's all guess work.