Enemy Lifebuoy? Enemy Lifebuoy? Are you serious? A LIFEBUOY is an enemy in this game?!
I see you are new to this. It can be explained with few theories: For japanese people, being offered lifebuoys after they failed their operation would be dishonorable, and even if they accept those lifebuoys, they will be either kept as prisoners and tortured, or be executed in public (due to how they are indoctrinated by their war code, or Senjinkun). They (the Japanese) people also not shy in using their wounded or dead comrade as booby trap, in order to go with final blaze of glory, so even after Geneva the Allies would be very cautious to take prisoners.