For the first time in the history of the high stakes Leaving Certificate Established examination in Ireland, teachers graded and ranked their own students due to Covid-19 restrictions. In the wake of the process, a questionnaire and focus group interviews explored how teachers engaged with the Leaving Certificate Calculated Grades 2020 (CG2020) and how they viewed their role as assessor. The process challenged the becoming of teachers in their personal, professional, and political identity, and it created a space where teachers’ feelings and beliefs oscillated between holding on to the traditional assessment approach and engaging in new possibilities of assessment reform. This paper maps what teachers were feeling and believing during the event of CG2020 and offers possible explanations for these responses through interrogating the molar, molecular and lines of flight of Teacher Assessment Becoming [Deleuze and Guattari. 1988. A Thousand Plateaus. University of Minnesota Press]. The feelings and beliefs of teachers as assessors offer potential lines of flight to reterritorialize through the reimagining of new assessment spaces, but there are many complex challenges to ensure that this reterritorialization does not regroup back into the old, striated space of previous assessment practices..