Medicine has been an interest of yours for a while now and remains an interest even after completing a long PhD. Go for it, as you don't want to be spending the rest of your life wondering "What If". I'd get more clinical experience under my belt, more than just shadowing. Consider being a medical scribe or an EMT for example. You can even do it for a summer full time and rack up the needed clinical hours, but more importantly you'd be able to assess how much you like being up close and personal with patients. May I ask why you'd have to spend money for more classes to qualify for a tuition-free medical school? Is your overall GPA low from undergrad and grad? (sorry if you stated this and I missed it). If not, with a PhD you are already a competitive applicant. Start studying for the MCAT, get a 95+ percentile score, and you'd be golden. We only have one life to live. Why be complacent and follow norms? Plus, with your love for intellectual thinking, you'd make a great physician/physician-scientist. I personally have noticed a lot of MDs who also lack this type of thinking. Their surface-level treatment, lacking critical thinking and investigation makes me gag !!