After defeating any of the B&B bosses they turn from beast to beauty form and attempt to hug you to death. I'm not sure if there's a hidden timer but after messing around with the hugging beauty for a while, the screen goes white and there's just Snake and the Beauty left on screen (with the UI) and a 3 minute countdown timer. What does this timer represent?
It is over after 3 minutes, they colapse and die. But as stated it is a sort of easter egg.
When their Beauty forms are advancing upon the player, not killing them for several minutes will result in transportation to an infinitely sized White Room, with a three minute timer. It is impossible to call Otacon or Rosemary while in this room. Equipping the camera will cause the Beauties to pose. If the player selects and de-selects the camera, they will change their pose. Equipping the iPod and playing "Oishii Two-han Seikatsu" will make them dance. When the timer expires, the Beauties collapse and die.