During the Tanker mission, if Snake saves his game, Otacon will try to recite proverbs like Mei Ling in Metal Gear Solid, except he will always mess them up. If you save your game and listen to Otacon's increasingly disjointed advice 13 times, a final codec call will be shown where in the middle of Otacon reciting a proverb, Mei Ling will enter the call via an audio-only transmission and interrupt him, try to correct him with a misplaced "cheat sheet" she made for him, and then scold him for losing the sheet and butchering proverbs with his own interpretations. Mei Ling will then tell Snake the correct meaning of the proverb, tell Otacon they have unfinished business, and leave the call. This is Mei Ling's only appearance in the game.
Contributed by MehDeletingLater