Background: In modern healthcare, the role of solidarity, altruism and the natural response to moral challenges in life-threatening situations is still rather unexplored. The COVID-19 pandemic provided an opportunity to obtain a deeper understanding of nurses’ willingness to care for patients during crisis. Objective: To elucidate clinical expressions of ontological situational ethics through nurses’ willingness to work during a pandemic. Research design, participants and context: A qualitative study with an interpretive design was applied. Twenty nurses who worked in intensive care (...) unit at two Swedish hospitals during the first, second, and third waves of the COVID-19 pandemic were interviewed. The analysis was interpretative and applied a theoretical ethics perspective. Ethical considerations: The study was approved by the Swedish Ethical Review Authority and informed consent was obtained from all participants. Findings: From a philosophical perspective, the nurses expressed sovereign life expressions of mercy and compassion, which arose spontaneously in response to seeing vulnerable fellow humans. They referenced ‘‘the nurse inside me’’ and their choice of profession as motives to provide care. Ontological situational ethics in culture and norms were noted in the constructs of competence, responsibility, solidarity with colleagues and organization; and interest and learning were driving forces. Ethical demand was evident when nurses expressed ideas of meaningfulness in helping their fellow humans; but themes of ambiguity, exhaustion and unwillingness were also present. Conclusions: The nurses showed a high willingness to care for patients during a crisis. Responding to the ethical demand and to care for vulnerable human beings while risking their own health and lives could be interpreted as an inter-human vocation. These spontaneous altruistic actions saved the lives of many patients during the pandemic and need to be understood and supported. (shrink)