In this chapter, we reflect on the specific instructional practices that emerge when newcomers in medical radiology gain access to such technical skills in the conditions of practice, under the guidance of experienced workers endorsing the role of mentors. The chapter aims at understanding how participants may use the patient's body as resources to navigate complex constraints associated with work procedures and epistemic practices. To do so, we adopt the theoretical perspective of multimodal interaction analysis and we use a collection of audio-video data recorded in a public hospital of the canton Geneva in Switzerland. Video recordings inform naturally occurring work and training practices as they take place during internships in a conventional radiology service.