It may have been missed in the earlier posts, but the fact that the warning horn is the same for both hydraulics failure and engine failure is really quite astounding.
I'm not sure how this got certified - anyone care to address this?
I've seen the video, but not studied it carefully - but there are a couple of places where the yaw appears to be pretty rapid, and possibly responsive to a tail rotor input.
We all need to wait for the investigation to work it's way through.