Current perspectives in cognitive linguistics highlight the conceptual nature of cognition and how the conceptual metaphors we hold affect ways we think, talk and act. This study examines medical educators' metaphoric talk to understand ways in which assessment relationships with students are conceptualised in order to understand why educators might 'fail to fail' underperformance in medical students. We conducted 10 focus groups with 70 educators at two UK medical schools. The audiotapes were transcribed and analysed using systematic metaphor analysis. The analysis revealed six over-arching metaphors associated with the target domain of assessment relationships, i.e. ASSESSMENT RELATIONSHIPS AS JOURNEY, WAR, SPORT, PARENTALISM, MACHINE and MEDICINE. While medical educators conceptualised students' academic failure in relatively innocuous ways (e.g. students' failure to arrive at their destination; journey), they also conceptualised failure in harmful ways (e.g. students' death; war). If medical educators hold the concept of ASSESSMENT RELATIONSHIPS AS WAR, it is perhaps unsurprising that they are reluctant to fail students. We discuss these findings in light of existing literature and provide recommendations for designing training sessions through which assessors can address reluctance to fail underperformance. Such faculty development may aid assessors in identifying and using alternative metaphors to conceptualise the assessment relationship.