The triage process in mass casualty incidents is a rare but highly mission critical task. First responding emergency medical personnel are confronted with high numbers of casualties and must quickly and correctly decide about severity of injuries and immediate care for every casualty. Consequently, effective training is crucial. Current training methods are either low in immersion and presence or both costly and resource-intensive. In this paper we present a virtual reality training simulation that aims to combine the best of both approaches. We use a human-centered design process and present a case study with 10 members of emergency medical services to outline design implications. While potential for optimization was identified, the evaluation results show the use of the simulation for triage training.