This paper offers insights into how mathematics education researchers can learn from preservice teachers (PSTs) by building upon parallels between adapting curriculum-making and designing research. The pandemic created learning opportunities for PSTs to anticipate mathematics curriculum anew and obstacles for researchers to study their pedagogical processes. A multiple case study reveals how PSTs in Year 1 and Year 2 of a Bachelor of Education program reimagined their intended mathematics curriculum to meet the demands of the evolving pandemic context. Viewed through the lens of complexity thinking and conceptions of "currere" and curriculum-making, PSTs' lesson redesigns include new contexts for teaching and learning (e.g., home environment, parental/guardian involvement, materials) that illuminate how curriculum researchers might become more tentative, responsive, and adaptable to unforeseen circumstances.