Hello there,
I'm a member of 80 000 hours, a community dedicated optimal career choice. I suspect they are your best bet for trying to answer this question. [Further disclaimer: the subsequent text should not be considered the 80k party line.]
I'm also a final year medical student in the UK, and my hunch is going for medicine is a better strategy, especially if you are trying to hedge against not being an elite scientist. If you go into medicine but it turns out you really are elite at science, transferring to a pure research career is doable (two of the people who taught me at Uni transferred from medical careers to being principal investigators at the LMB). If not, one still tends to make a lot of money, so one can fund other researchers etc. If you lose the gamble as an academic, things are unlikely to turn out so well.
The one big counterveiling factor is motivation. Going through medical school is not easy if you aren't interested in treating patients. If you dislike/have difficulty with communicating with people, you will likely have trouble getting through the exams. Providing that is okay, though, it should be feasible.
I graduated from high school and wish to further my education formally by studying for a bachelor's degree in order to become a medical researcher. I could, for instance, take two different academic paths:
Study Medicine at undergraduate level and then do a postdoctoral fellowship.
Study Biochemistry at undergraduate level, then study for a PhD at graduate level, and finally do a postdoctoral fellowship.
Since I will do these studies in Europe, they each take approximately the same amount of time, namely 6 to 8 years.
Do I want to do treat patients? No, I do not. But I am considering Medicine because it can be a buffer against my own mediocrity: in case I turn out to be a below average scientist, I will be screwed royally. From my personal job shadowing experience, Medicine, on the other hand, requires mere basic intellectual traits, primarily the ability to memorize heaps of information. And those I think I have. To do world-class research though I'd have to be an intellectual heavyweight, and of that I'm not so sure.
How do I decide what path to follow?
The reason I'm asking you strangers for advice is because I evidently have biases, such as the pessimism/optimism bias or the Dunning–Kruger effect, that impair my ability to reason clearly; and people who know me personally are likewise prone to make errors in advising me because of biases like, say, the Halo effect. (Come to think of it, thinking that I can't become an above average scientist is in itself a self-defeating prophecy!)
Do you think that one ought to always seek advice from total strangers in order to be safeguarded from his/her own biases?
PS: I apologize if I should have written this in a specific thread. I'll delete my article if that's necessary.