Back on the boat after a wonderful and uneventful dive, Bob starts walking over to Karen to do a post dive debriefing...just then a rogue wave hits the boat, and Bob, being unprepared due to the calm surface conditions, topples backwards, inadvertently putting one foot in the rinse tank. This causes him to fall backwards right onto a knife being held up by a diver who is inspecting it for surface rust.
The knife cleanly severs Bob's right testicle which falls to the deck with a "plop" sound. Bob falls to the deck, bleeding profusely from the severed testicular artery but all divers are watching in stunned silence as Bob's testicle rolls around the deck and finally through one of those oval openings on the side of the boat that has claimed more than one piece of diving gear, and into the ocean with a splash.
Karen thinks quickly, recalling the Lorena Bobbit incident and the successful reattachmnent, and she grabs a weight belt and dives over the side, bent on recovering the lost testicle. In mid stride (and midair) she clips the belt to her hip but lands on a sea turtle that has surfaced next to the boat.
She's knocked unconscious by the impact of her head against the turtle's shell, and she falls to the bottom of the sea...minutes later Bob's testicle lands next to her to join her in her watery grave.