Spatial dispersion of casualties and temporal dynamisms of emergency resources are the two critical factors that complicate the casualty management operation in large-scale mass casualty disasters. These factors are studied in this project to develop an optimal strategy for traffic control in a casualty treatment station that provides first aid assistance for severely injured casualties on the field. This study shows that the optimal strategy to save the highest number of casualties at a treatment station with nonstationary arrival and treatment rates is dynamic with time-dependent resource allocation and casualty prioritization schemes. The proposed dynamic strategy is compared with static strategies used in practice. Findings show that the expected performance of the dynamic strategy is always better than the static approaches regardless of the disaster severity level. Also, the over-performance of the dynamic strategy is not affected by the tentative errors that may happen in estimating the parameters of the problem. We show that the shortage of search and rescue resources mitigates the over-performance of the dynamic strategy. In contrast, the medical resource shortage amplifies the importance of implementing dynamic treatment strategies.