Military education is for most people an unknown process that takes place behind closed doors. Based on text analysis, eighteen months of ethnographic fieldwork, and interviews at the Netherlands Defence Academy, this article seeks to understand military education as a dynamic process between the cadets' experience and the institute. As such, this study can be understood as an institutional ethnography, intending to open the black-box of military education. This study shows that military education affects cadets in a powerful way. They quickly learn to navigate the 'underlife' of the institute by carefully avoiding confrontation with the official structures. In a final discussion, we identify two remarkable paradoxes -- "perfect imperfection" and "individual in the system" -- that we consider exemplary for the learning environment at the NLDA. We argue that the Defence Academy constitutes, in essence, a paradoxical learning environment that influences the character development of the cadets -- sometimes in unintended ways.