Is that possible to bring Cube to Tanner?
Yeah, you just take the cube and export your character, you start the game in another timeline, and follow main storyline until next cube is stolen by tchorts, then you descirpt its apperance to tanner and when he commands you to bring it to him, you have option that you already have it. He take it, and you have a cutscene when he walks into his room, locks the door behind him and this triggers secret time paradox ending, where Six is so angry that kills player on the spot.