the information you have provided will be of great value in the future..
Agreed.
.....does not convey the shock you going to be subject to when you hit very cold water at very high speed in a very hostile and completely overwhelming environment.
Agreed. Surviving/containing/controlling the intial technical problem and getting to the surface in one piece is one thing, once you hit the water you are into a whole different ballgame and on possibly on a very tight time line.
( Mountbatten course early 80, unexpected practical exam the following winter....)