It won't have sunk straight down, essentially it will have flown underwater potentially for quite some distance. Of course locating it and recovering it are two different things, it's likely they know roughly where it is but until the recovery vehicle is in place there's nothing they can send down to confirm things.
Thanks for your thoughts, Skippy,
It looked like it pretty much flopped off the ramp, so to my mind, would have not glided all that far. I'm not relying on solid knowledge, just personal thoughts. Maybe I even misunderstood the video.
Think of it like dropping a plane from 5000 feet. It'll drop nose down initially but then as speed picks up the nose will rise and it will start moving horizontally. The only difference is that the sea is much denser. Of course the open lift fan door is going to have some sort of effect, but even ships don't sink straight down.