Based on the new materialism’s theory of appropriation relationship which emphasizes the dynamic co-construction and reconfiguration of agency, this study examines the practical configurations of “Teacher-Student-AI” triadic interaction modes in medical education. Using the globally contested case of abortion, the research analyzed 454 online ethic assignments for Chinese and International medical students to show knowledge transmission model, critical recognition model and designed creation model. These models vary on the knowledge internalization, critical thinking activation and student agency improvement. Based on these, we advocates that educators should holistically integrate the modes to construct a graded and progressive pedagogical pathway. This approach employs the human-AI boundary design, critical domestication of technology and innovation-driven practices to enhance medical students’ theoretical literacy and critical reflective competence.