The start of the COVID-19 pandemic early 2020 has confronted healthcare sectors with risks and uncertainties on an unprecedented scale in recent history. Healthcare organisations faced acute problems, the answers to which had to be provided, and recalibrated, at short notice and informally. University hospitals played a pivotal role in providing these answers and in (re)calibrating institutional arrangements. Based on ethnographic research in an elite university hospital in the Netherlands, in this article we explore the concrete practices of governing risks and uncertainties that COVID-19 posed for the organisation of healthcare. Our fieldwork consisted of the observation of meetings at the level of the hospital boards, the staff, and the regional level. We collected relevant documents and interviewed key-actors. This approach offers us a large dataset on acute risk governance ‘from within’ and allows us to offer a layered ethnographic account of managerial practices. In our analysis we focus on conceptualising the work-as-done in the university hospital as risk work. We show how the risk work of our participants is generally characterised by high speed and delineated by scarcities. We differentiate between three modes of risk work: working on numbers, working on expertise and working on logistics. This risk work appears innovative, but our analysis stresses how participants’ work happened in interaction with traditional institutional logics and routines.