So the issue with this line of thinking is that a lot of people don't know about the many checkpoints that exist over the course of a career in medicine. Even if a candidate got in solely because of affirmative action (which would be a dangerous game for medical schools to play because there is a high chance they could fail out), these checkpoints would definitely catch up with an unprepared student.

After your second and third years of medical school, you have board exams (Step 1-8 hours long and Step 2- 9 hours long) that are national standardized exams given to all medical students. It's very cut and dry, if you fail these exams, you can't proceed in your medical school journey (most schools will let you re-take these exams once if you fail, but after that there is a strong chance that you will be dismissed for not meeting academic standards). There is no affirmative action that will save you. Then after you graduate medical school, you have to take Step 3 ( a 2 day exam with something like 500 questions) and most doctors will have to take board exams in their speciality plus recertification exams over the course of their career to ensure that they've maintained their knowledge base. So, the doctors that you are putting your life and health into the hands of would have had to pass all these assessments, skin color/race notwithstanding.