[MS90]

I remember watching the Discovery channel series BUD/S 234 about SEAL training, it stuck out to me that during their swimming test where they're required to swim an entire lap of the pool underwater that the first thing they're required to do when they come up is yell "I FEEL FINE" as loud as they can.

Anyone who didn't do so was instantly hauled out of the pool and sent to the medic. Which was good, because some of the men were unconscious when they got there, though they still passed the test! The requirements were to swim down, touch the far wall, swim back, touch the near wall, all while remaining underwater. State of consciousness was never specified :)