Based on what I’ve learned from admissions committees and advisors:
1. Masters is harder than Bachelors, so it should help make up at least some. Since your graduate work was in the biological sciences I think the GPA speaks well for your ability to handle the sciences.
2. Military = commitment and hard work = important to med schools. Think of how many students get their med school funding through military agreements.
3. You’re 31 and applying because of military commitments… not just because you needed 8 years. Show them (in essays and interviews) that you are aware that you’ll be 40 years old or more by the time you finish residency and that doesn’t bother you.
4. Each school is looking for diversity, talent, and good future doctors, but some are more open-minded than others. I wouldn’t consider many to be very closed-minded except in expecting a certain level of academic excellence – but that’s a product of the number and type of applicants apply for so few spots.
5. Get some clinical experience to show your interest in medicine and nail the MCATs. Those two things would answer their major questions about you. Also apply to plenty of lower tier schools and higher tier schools.