Despite being a very experienced Diver but not current at the time of the training in the pool....it was not exactly a piece of cake. No big deal just dropping down and breathing while up right but upside down with legs hung over the side of the pool edge was a bit of a trick to cope with.
Now as to trying that without being an experienced Diver, for real in cold water, following a hard impact....well at least your odds are improved but how much really?
In Pool training is a must!