Healthcare work in extreme situations is the guiding principle of this paper, which investigates the activity of workers in the NGO Doctors Without Borders, seeking to understand the uses of self in the confrontation with the reality of healthcare work, help and lifesaving. The challenges posed by complex contexts make this work more demanding, exposing the vulnerability of patients, workers and organizations, but also their capacity to confront and overcome difficulties. Schwartz’s ergological perspective, the Psychodynamics of Work and Canguilhem’s conception of health provide the theoretical-methodological direction to the qualitative research that used interviews as well as visits to MSF Operational Centers. The results show a challenging activity, where there is desire, institutional protection and professional appreciation ; but also strain and the pressure for a “normal” life ; conflicts of values, and the relevance of cooperation for the preservation of the sense of work in humanitarian care.