We describe and analyze our efforts to support Learning Assistants (LAs)—undergraduate peer educators who simultaneously take a 3-credit pedagogy course—in fostering equitable team dynamics and collaboration within a project-based engineering design course. Tonso and others have shown that (a) inequities can “live” in mundane interactions such as those among students within design teams and (b) those inequities both reflect and (re)produce broader cultural patterns and narratives (e.g. Wolfe & Powell, 2009; Tonso, 1996, 2006a, 2006b; McLoughlin, 2005). LAs could be well-positioned to notice and potentially disrupt inequitable patterns of participation within design teams. In this paper, we explore (1) How do LAs notice, diagnose, and consider responding to teamwork troubles within design teams, and (2) What ideological assumptions plausibly contribute to LAs’ sensemaking around their students’ teamwork troubles? To do so, we analyze how the LAs notice and consider responding to issues of equitable teamwork and participation, as exhibited in three related activities: (i) an in-class roleplay, (ii) observing and diagnosing teamwork troubles (TTs) in the engineering design teams, and (iii) imagining possible instructional responses to those troubles, and students’ possible reactions. We articulate three modes of thinking that roughly capture patterns in LAs’ descriptions and diagnoses of, and imagined responses to, the teamwork troubles: individual accountability, where the trouble is seen as caused by individual(s) described as “off task” or “checked out” or demonstrating some level of incompetence; delegation of work, where the trouble was located in the team leader’s inability to delegate tasks effectively to team members, or in the group’s general lack of communication about what tasks need to be completed, who should execute the tasks, and what work other groups in the team were doing; and emergent systems, where trouble was described as a group-level phenomenon emerging from the patterns of interaction amongst group members, contextual features, and larger structural forces. We find that LAs drew on individual accountability and delegation of work to evaluate TTs. Much rarer were ascriptions of TTs to interactional dynamics between teammates. We connected these modes to the underlying ideological assumptions that have consequences for how meritocracy and technocracy (Slaton, 2015; Cech, 2014) play out in an engineering design classroom and serve to ameliorate or reify engineering mindsets (Riley, 2008). The modes are asymmetric, in that emergent systems based interpretations hold more potential for elucidating ongoing social processes, for challenging meritocracy and socio-technical duality, and for seeing power differentials within interpersonal and institutional contexts. We argue for the need to better understand the ideological assumptions underlying how peer-educators—and other instructors—interpret classroom events.