Code Orange is a multiplayer 3D serious game being developed by SiTEL for hospital mass casualty incident training. The game places up to 12 human players in key hospital roles where they must work together in real-time to respond to a simulated terror attack. By immersing trainees in a realistic virtual hospital, Code Orange aims to more effectively teach the procedures, communication skills, and strategic decision making required during a real MCI when normal rules change and resources are scarce. The game is being designed based on input from medical experts and will integrate with SiTEL's learning management system to support ongoing analysis and improvement of training.