Clinician silence in the face of known threats to patient safety is a source of growing concern. Current explanations for the difficulties clinicians have of speaking up are conceptualised at the individual or organisational level, with little attention paid to the space between – the interaction context. Drawing on 103 interviews with clinicians at one hospital in the United States this article examines how clinicians talk about speaking up or not in the face of breaches in infection prevention technique. Accounts are analysed using a microsociological lens as stories of interaction, through which respondents appeal to situational and organisational realities of medical work that serve to justify speaking up or remaining silent. Analysis of these accounts reveals three influences on the decision to speak up, shaped by background conditions in the organisation; mutual focus of attention, interactional path dependence and the presence of an audience. These findings suggest that the decision to speak up in a clinical setting is dynamic, highly context-dependent, embedded in the interaction rituals that suffuse everyday work and constrained by organisational dynamics. This article develops a more sophisticated and distinctly sociological understanding of the reasons why speaking up in healthcare is so difficult.