I'm not sure if it is exclusively biomedicine, but the reason I would supsect it wreaks more havoc on someone in a biomed degree than commerce would be a) Commerce has fewer hours in general for which there could be a potential crash, b) There are more commerce students, and subsequently, many lectures have more than one stream - if one clashes with accelerated maths (for which there is only one stream of lectures), there is usually a repeat in the afternoon. This latter reason applies equally to science students, who have about as many contact hours as Biomed, but with more streams as their subjects are generally huge. Biomed only has one stream of lectures for the majority of its core subjects (eg. Biology, Chemistry, Stats) - these are in the morning, which is when accelerated maths is on.