The present chapter seeks to promote a methodological discussion around the pertinence of drawing on retrospective reflexive ethnography and the notion of ‘past presencing’ to investigate the practice of interpreting in field missions deployed by the United Nations. The chapter provides an overview of the methodological choices that were made after analysing the implications of the second author’s positionality as an insider and after considering the different methods that could be used to make the most of her wide experience as an interpreter who had been deployed to many field missions. After highlighting the particularities of practical issues related to interpreting in said missions, we examine the application of the findings to design and implement interpreter training, which brings about institutional changes at the UN that will eventually have an impact on the interpreters’ work.