This paper presents The Desk: Dilemmas in AI Ethics, a digital game-based learning approach to enhance learning about AI ethics. Grounded in the social intuitionist model of moral judgment, the game fosters intuitive moral reasoning and collective decision-making through the narrative of a newspaper editorial desk. The game design incorporates four key mechanics to support moral judgment and reasoning: (a) three-player dialogue settings, (b) separate individual and group decision-making spaces, (c) dilemma scenarios based on conflicting moral foundations, and (d) both positive and negative feedback from the public. The initial design, featuring six scenarios centered on the ethics of “Killer Robots,” was tested with three groups of nine players. Their in-game discourse was analyzed using the Moral Foundations Theory. The results indicated that the dilemma scenarios effectively supported players' ethical reasoning on whether society should adopt AI killer robots. Players engaged in moral reasoning based on different moral foundations depending on their supportive or opposing stance. The findings also highlighted how individual intuitive judgments conflict with collective agreements in group discourse. Overall, this study presents a new pedagogical approach to AI ethics education through digital games and dilemma-based discussions.