In University Modeling Instruction, small groups work on a problem and then hold a student-led wholeclass discussion ("board" meeting) to develop consensus. In practice, some students regularly contribute more to these discussions than others, and end of course evaluations indicate not all students value them. To better understand those two phenomena, we had students in a university modeling classroom write about their experience after a particularly contentious board meeting. Because this highly participationist pedagogy requires students to be social while learning, we modeled the UMI classroom using Wegner's "Communities of Practice". In particular, to analyze student responses, we developed a preliminary code based on Wegner's social ecologies of identity framework describing student identities of participation and non-participation situated in the context of different modes of belonging within a community of practice. Student responses were sorted into three broad categories based on their descriptions of their experience during the board meeting. We developed our preliminary code by analyzing one student response from each of the three different categories. Initial coding of these three students' responses reveals a rich description of their different experiences during a contentious board meeting in the UMI classroom. Our intention is to continue coding the remaining student responses to further develop a robust description of this particular contentious board meeting. In building this descriptive model of student participation, we seek to develop a predictive model to inform professional development for instructors who teach with this pedagogy.