Did she go to the open days at Cambridge? What are her preferences on college size and location ?
She might want to be nearer lectures and the hospital. Or in a college with an active medical society, like Christ’s College.
If she didn’t go to the open days or consider it before, then she should think hard about why she’s changed her mind now. It shouldn’t be about applying for the most prestigious university she ( of the school ) can think of just because she has a good UCAT score.
She will be there for 5 or 6 years and should choose a location and course that she thinks are the best match for her. There are many “ top medical schools “ in the UK, not one or two. She won’t gain any great advantage in her career compared to studying at say Imperial , Bristol or Edinburgh.
re Cambridge - not everyone enjoys the longer course, the divide between Clinical and preclinical years , the heavy academic workload with a focus on research and the independent learning style in the clinical years .
Students who have only done science and maths A levels often find it hard that assessment is based so heavily on essays. You have to hit the ground running as your marks in first and second year count towards your final degree, so there’s a lot of pressure.
I think she needs to be sure that the structure of the course and the environment and teaching/ learning style are right for her. That’s more important than choosing a college in 48 hours!
Remember that some schools push applicants into applying for Oxbridge even when that’s not the best choice for them, as it pushes them up some league tables.