The responses of higher education (HE) institutions towards the climate crisis and escalating social inequalities have been researched from either 'top-down' (i.e. institutionally-led) or 'bottom-up' (i.e. student-led) perspectives. As scholars call for enhanced insight into the space between these two poles, this paper provides an autoethnographical account of a 'bottom-up' network led by doctoral students -- Researchers 4 Sustainability (R4S) -- initiated within a UK university to contest 'top-down' structures by way of disciplinary silos. Likening disciplines to communicative subsystems, we draw on a social constructivist perspective of dialogue to demonstrate how three forms of dialogue -- exploring, explaining and expanding -- support not just the transcending of disciplinary boundaries, but crucially, institutional hierarchies, in the creation of sustainability knowledge. Herein, we introduce a framework against which to organise student-led dialogues relative to their inter- and/or trans-disciplinary orientations and offer recommendations for theory and practice.