Serious games show great potential, but many fail to live up to that potential. One way to improve serious game design could be to introduce surprising events linked to the instructional material. We modified our serious game for triage training, called Code Red Triage, to include three surprising events pertaining to decision-making moments in the triage procedure. Forty-one participants were divided into two groups: one group played a version of the game with the surprising events, and the other group played a control version of the game. A pre-posttest design showed no significant difference in engagement and surface learning, but did show the participants in the surprising events condition obtained significantly superior knowledge structures, indicating that surprising events in a serious game foster deeper learning.