Too much misinformation in this thread.
With regards to shoes: In your most conservative suiting i.e. charcoal and navy solids, black shoes are ideal, especially with black buttons. A dark burgundy can look good with navy as well, but not too hot with charcoal. Dark brown is acceptable with either when buttons are changed to a dark horn, but again, not ideal.
The reason brown is considered "better" than black on SF (a lot of SF lurkers here it seems) is that brown is preferred over all instances except the above i.e. lighter and non-solids suits and odd jackets/trousers. Brown shoes also develop that highly desirable patina while black shoes just stay black. My advice: unless you're wearing less conservative suits or odd jackets on a frequent basis, go with a black cap toe balmoral. Black park avenues are fine. Hell black J&M or Florsheim are okay, too. No need to drop $350 for PAs or $200 for PA seconds when all you're going to wear them for is med school interviews.
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With regards to suiting: Medicine is not a conservative field. CBD is not preferred in the field, and there's no strict hierarchy as with finance or law. Most likely, med school interviewers won't really care what type of suit you show up in. My advice: Navy or charcoal suit with notch lapels 3" or wider. Tie matches lapel width, and novelty patterns and bold colors should be avoided. If you want a pocket square, white linen w/ a neat flat fold (no points or puffs).
Unless you're confident in your measurements, buy your suit off the rack and get it tailored and avoid made-to-measure. Fit before quality. A fitting cheapo Hugo Boss will look better than an ill-fitting Kiton. Unless you have an interest in tailored clothing and wear it often, you (and likely the interviewer) won't be able to tell the difference in quality anyway.
None of this advice is hard or fast. Lapels can be thinner or wider by taste. Peaked lapels are probably fine, too. The Harvey Specter look may be a little too bold, however, with its combination of wide peaks and strong roped shoulders (not like any of us can afford Tom Ford/Zegna Couture anyway). Orange grenadine tie with navy? Go for it if you want. As aforementioned, medicine is not a CBD field.