If you are referring to this:
Then you're right.
HOWEVER, this is from an Instruction movie!!!
THIS:
Was wartime practice.
It's simple: When battle surface was ordered, the crew wasn't wasting any time to get up the deck a.s.a.p. Anything on their body that might delay this thrown out. So vests and helmets...bye bye.
And yes, unfortunately some crewmembers were washed over board and alas drowned because of this practice.
groetjes,