What Is The Movie Called Where The Two People Get Left Out At Sea Because They Went Diving And They Got Left?

and they get almost eaten by sharks

Is It True Those Scuba Diving Outings On Big Boats Are Dangerous Because The Staff Forgets People And Leaves?

them behind sometimes?
Like they forget how many people were in the water, and so they will abandon people in the open sea without realizing it till the next day? So these unfortunate people drown, or are eaten alive by sharks, or other horrible things happen to them?