On the deck, the unconscious sailors are rolled on their sides, and as soon as they revive, an instructor shouts again and again: "Are you gonna quit? Are you gonna quit?" Sailors are given 30 seconds to answer or they're kicked out of the program.
A lot their "training" seem designed to weed out those who lack specific innate traits. From what I understand the goal is to cull most people as soon as possible and then train those who remain which suggests they focus on innate talents rather than testing people after they have been trained. Which IMO is a good idea, because you don't know what you are going to face in the real world.
PS: You see the same idea with a large high school's football camp. The first few days is all about weeding people out based on physical fitness.