Emergency response teams —police, firefighters, and medical— must effectively coordinate their actions in high-stress situations. Current training programs primarily focus on technical skills and rigid communication protocols, yet maintaining or flexibly adapting coordination under stress is equally critical. By using a novel multi-channel approach that synchronizes video-coded coordination behavior and physiological measurements across three contexts, I examine complex coordination dynamics in high-stress scenarios. Insights from this research will inform the development of intervention and training methods to support teams in maintaining effective coordination under stress.