We study physicians’ subjective experience of cooperation, in the context of complex scenarios in a French emergency medical centre (called Samu). The aim is to understand how the physician experiments and manages the teamwork, and how cooperation is either promoted or hampered through the interactions with the person making the call, and other team members (call-takers and other physicians). We draw upon theoretical frameworks that focus on the inherently subjective dimension of cooperation, and present two case-studies based on explicitation interviews. The results highlight that the caller, or even the patient, is able to develop the key resources that are needed to co-construct a shared context, remotely refine the diagnosis, take a decision, or follow instructions on a medical procedure. We also highlight experiential knowledge, such as the physician’s attentional dynamics, which reveal very brief cooperation configurations as a function of the first-person point of view. Finally, interpersonal trust is shown to be at the heart of unfolding cooperation dynamic in real-life scenarios requiring teamwork.