This paper describes and analyzes the central role of human–human communication in a dynamic, high-risk environment. The empirical example is a UN peace-enforcing and peace-keeping operation where uncertainty about the situation in the environment and about the own organization’s capability was intertwined, requiring extensive control activities and, hence, special attention to communication between humans. Theoretically, focus lays on what efficient communication means, how to understand and use social relations, and use technology when making socio-technical systems also cooperative systems. We conclude that “control” largely is based on the ability to communicate and that efficient human–human communication is grounded in relations between individuals, which preferably should be based on physical meetings. Uncertainty, and how humans cope with it through interpersonal communication, is exemplified and discussed. In theoretical terms, relating the study to systems science and its application in organizational life and cognitive engineering, the case illustrates that an organization is not only an economy but also an adaptive social structure. But neither cognition nor control is an end state. The organization’s raison d’être in this kind of operation is cooperation rather than confrontation. Its use of force is strictly regulated by Rules of Engagement (ROE). In the organization, strong emotions may govern, interpersonal trust can be established and rule-sets for further cooperation established. Without considering the power of such aspects, economical rationality and detached cognitive thinking may end up in perfect, but less relevant, support technologies where people act in roles rather than as wholes.