This paper investigates the practice of role-playing used in vocational training in the workplace context in order to train students to conduct interviews with patients. It concerns the professional training of nurses in Switzerland dur-ing work placements. By adopting an interactional perspective on work and training, the paper offers a case study of the content and practices used to conduct a role-play activity. The analysis of audio-video recordings of naturally occurring training practices enables studying the fine-grained details of the interactions in a comprehensive ap-proach. The focus is on the practices of listening which require the interpretation of the speech of the other partici-pants. The objective consists in exploring how the trainer enables the students to identify the elements that are rel-evant for an anamnesis on the basis of her interactional conducts as a simulated patient. The results show that the oscillation between role-playing and transmissive moments forms an engineering-in-act of vocational training which makes it possible to vary the practices that “hide” or make visible elements of the situation in order to make them “learnable”.