My thought process:

Okay. So, Doha knows how to end the game. We know this, because he found that piece of paper that he or Seongchan probably wrote during their past/original memory/tape save, and tears it up so Bada doesn’t find it. He also keeps manipulating the game and other players, so that Bada doesn’t find clues to bring the game towards completion. Bada is an NPC, like the NPC that Seongchan, a player, taught to guard the room with all the tapes and the multi-tape player. Bada is there to help the players along the way so they can complete the game, just like the other NPC. It doesn’t matter if Bada’s memory is wiped and a new save tape is made, Bada always figures out or finds something new to keep progressing the game. I.e. Bada is the key towards completing the game. Here’s what I’m thinking. Seongchan stopped playing all the other players tapes, so he could go off on his own and finish the game by himself. The only thing that he didn’t take into mind was the fact that Bada would possibly start or stop other tapes from playing. I have a feeling that Bada somehow stopped all the other remaining players tapes through his attempts of trying to escape the game (when he would find a tape and then put it in a tape player), then at some point restarted Seongchan’s last play-through and one of Doha’s early/mid-game play-throughs. I have a very bad feeling that Seongchan is hiding a very big secret. Kind of like how, in Wreck-It Ralph, King Candy is actually Turbo from TurboTime that changed the code in Sugar Rush to take over Vanellope’s role as the ruler in the game, and basically erase her/cause a glitch in the game? What if Bada is the true player of the game and has now become an NPC, because the actual NPCs became sentient and switched their “code” with Bada’s? What if Seongchan found out that only one person, the player that completes the game, is the only person that will be able to leave the game? Maybe Doha found this out as well, and, at first, wanted to manipulate Bada into helping him finish the game, but then decided to abandon the idea altogether, due to his growing obsession for Bada. Would that count as some kind of a reverse Stockholm syndrome kind of thing? Idk fam, I’m just here hoping that this isn’t just someone completely random playing the game, and what we are witnessing is their multiple play-throughs/game saves.