Cell division is one of the most relevant processes in Biology, for instance, to understand the reproduction of species or the development of tumours. Learning this content requires not addressing it out of context but integrating it into real-life problems that demand students apply their knowledge about cell division. In this study, the authors examine how ten small groups of 10th grade students apply their mitosis models to solve a problem about cancer treatment; and how they progress in their application in terms of students' discursive moves. Throughout their discussions, learners must explain what happens to a treated tumour cell which cannot finish its division. To do so, they should consider understudied ideas such as the prometaphase stage or the importance of bipolar spindle formation. Data collected are the groups' audio recordings and their written reports. The results show that all groups handle notions, such as the need for centrosomes' duplication or microtubules-chromosomes' attachment for mitosis to be complete, throughout the activity. Although all groups integrate two or three ideas at a time into their discourse, none of them manage to combine and contextualise all the expected ones. Implications for Biology education are discussed.