This paper draws upon Foucault's problematisation of "governmentality" analysis to explore teacher interviews from Australian secondary schools, where student voice was 'enacted' within a teacher assessment reform strategy. By bringing teacher voices into relation with theory, it illustrates how the current 'sociality of performativity' is situating student voice-based assessment initiatives as power apparatuses of teacher surveillance that shape teacher-student relationships. The analysis portrays teachers' responses to such 'techniques of power', employing forms of "auditable commodification," "physical proximity," and "reflective practice" as a means of managing student voice 'risk'. In so doing, the teachers relegated teacher-student relationships to the margins, struggling to profess an ethic of care; paradoxically disadvantaging students through voice initiatives intended to advance them. Demonstrating how affective fundamentals are eclipsed by performative-invested practices, the analysis highlights the discursive policy contestations of rapport and performance that should be taken into consideration in future implementations of student voice-based assessment initiatives.