The present study aims to understand how the professional vision of prospective teachers (PTs) regarding whole-class reflective discussion develops as they explore a multimedia case (MC) in a mathematics teacher education course. The data come from the written productions of seven groups of PTs (N=15) related to whole-class discussion of one 6th grade lesson in two sections of the MC: first, they have focused on the teacher's lesson plan and on her intentions for the whole-class discussion aiming at the students' algebraic thinking; and in the second, they have analysed two video episodes of that lesson phase. The results show an integrated development of two processes of PTs' professional vision -- noticed events and the nature of the reasoning about them -- with significant evolution from one section to another as they explore the MC. The study shows PTs' alternative ways of accessing and making sense of the complexity of both ambitious and authentic teaching practices that can also be employed in at distance teacher education and mitigate the consequences of the impossibility to access the classrooms, such as that resulting from the recent COVID-19 pandemic.