This article uses the notion of a "sensitising concept" in order to understand insider and outsider dynamics in cross-organisational field research. The analysis is based on a study of learning and innovation in the social and health care educations in Denmark. As these educations combine classroom training and workplace internships, the students and educators frequently cross organisational boundaries as part of their training and educating. In my attempt to understand the boundaries as learning and innovation resources, I reflect on my own shifting insider and outsider positions as a field researcher. It is argued that the researcher's experience of changing insiderness and outsiderness in cross-organisational field studies can serve as a starting point from where to investigate emotional and material aspects of boundary-crossing.