If you are IS for Colorado (based off your other post) I assume that means you're OOS for Missouri...which sheds a little bit of light on things as Mizzou is very IS biased (statistically). But still, you're a great applicant on paper, so assuming your LORs/ECs/PS/Interview didn't red flag, I see no reasonable cause for you to get a rejection so early, even with being OOS. I wish you the best, and sorry things didn't work out.
You are correct that I am OOS for MU, but I do have strong state ties (born and raised in MO, attended MU during UG and graduated from Columbia College, all family still in central MO, etc) and have only been in CO a few years. My EC’s are probably on the lower end (I work a full time M-F job as well as part-time side jobs which has made it exceptionally difficult to get shadowing hours that work with my schedule so I’m on the lower end there). I also have some volunteering (clinical ~120 hrs @ VA ER, ~50 hrs non-clinical, 700 hrs of research, several academic honors, awards, etc). I received a lot of positive feedback on my PS and secondary essays from both physician friends and others I had look over them. My LOR’s were very strong based on the feedback from the letter writers so I don’t think that was the issue.
As far as the interview, I didn’t feel that they went great as they felt somewhat hostile/aggressive but I felt that I handled them well. As a non-trad I have had many professional interviews and felt well prepared and comfortable with that part of the process. I had great feedback from mock-interviews I did and felt that my performance in the real interview was similar. I guess my perception could be off here and the interview may have been the issue but I’m really not sure. All in all I thought I would at least be waitlisted so I was surprised and disappointed to get the R after a month without even making it to the March decision. I guess it just wasn’t meant to be though, so I’m still holding out hope for one of the last interviews from CU or SLU. Regardless, best of luck to those of you still waiting on a decision!