For me, I grew up around a family of nurse and my brother was an EMT and an AT. I hated blood, I wasn't interested by the stories, so I was CERTAIN I didn't want to go into healthcare.
And then I went to college where I found myself in love with Psych and researching what I could do with it that wasn't counseling and found OT and that was it for me. Switched my major to health sciences and well, now my family likes to joke about how I am now in healthcare when I swore up and down I was going to teach.
So for me it wasn't a choice of OT or Med School. People at my university like to think of PT/OT as a second choice because we "couldn't handle pre-med"or it was "too hard" and we "settled."
I just never had an interest to begin with.
Edit: Also, never go into a career for money. If you don't love what you do, it will always be work and it will always be a pain in the ass to get up in the morning. I know for sure I'd much rather be an OT and make less than being an MD than be (personally) absolutely miserable.