How valuable is getting higher quality research mentorship in college?

I wonder how much attending different universities matters if we focus solely on the quality of research mentorship available to an EA-oriented student who hopes to reduce AI risks.

I plan to study dentistry at a medical university because I believe having earn-to-give as a backup option is important. However, my ultimate goal is to become an AI safety researcher. I therefore plan to collaborate with computer science professors at a nearby university and may spend around 40% of my time in college on AI-related research.

Suppose Medical University A is located near University C, which has a top 5 computer science department in Taiwan and around 60 professors working in CS-related fields. Medical University B, meanwhile, is near University D, which ranks around the top 10 and has approximately 35 professors in relevant fields.

University C is clearly stronger overall and would probably give me a better chance of finding a lab doing a more EA-aligned research topic. This gives Medical University A an advantage, but A is also more difficult to enter.

For example, suppose I were admitted to Medical University B through the first entrance exam. Would it be worthwhile to spend around three months preparing for another exam in order to enter Medical University A for better research mentorship? (assuming that I would get in medical university A on the second exam and that the two medical universities are otherwise similar?)

Even if you are uncertain, your 1-minute gut intuition about this topic would already be very helpful. Thank you very much for your time.