The players see the bodies of Player 111 and his co-conspirators strung up for cheating, and are assured that the games are designed to give every player a fair chance without discrimination. For the fourth game, players are told to pair up, but discover that instead of working as a team, they will have to play against their partner in a marble game of their choice. Whoever gets all their partner's marbles within 30 minutes will win and survive. Sae-byeok and Player 240, named Ji-yeong, share their life stories; Ji-yeong sees Sae-byeok has more to live for and sacrifices herself. Sang-woo tricks Ali into giving up his marbles and wins, which results in Ali's death. Deok-su wins against his partner and henchman, Player 278. Gi-hun exploits Player 001's dementia to defeat him, only to discover that Player 001 had been aware of the deception the entire time. Player 001, who remembers his name to be Oh Il-nam, allows Gi-hun to win anyway, as he is his gganbu (trusted friend). Gi-hun and Sae-byeok are traumatized by the deaths of their friends.