Not everyone has a marker telling you they are or have been in the military either. Are you? You don't have the marker but that doesn't mean you aren't. The very fact that I do not know means I would call you sir or be formal in a formal setting. Guess what Mr. Schlitter, a Med school interview means you are interviewing to be a PROFESSIONAL...did I stutter...yes that is right a PROFESSIONAL in a highly respected and regarded field. Are you interviewing to be a personal trainer, maybe a waiter or a cook? Maybe a UPS driver. No, you are interviewing to be an 'F'ing physician.
My last commander was a professor at the local medical school, he is a reason I applied and got into medical school (different school and state even).
Be respectful, professional an courteous. The person not only is interviewing you to enter as a PROFESSIONAL in one of the worlds more respected professions but is evaluating you as a person in general. NOT ONLY THAT...but keep in mind I have been in the process of interviewing and know that many medical schools have an interview portion with some second years of the school. If I had interviewed you I would pick up so quickly on how much of an immature and simple minded individual you are that admittance for you would be nothing but quick laugh then a check in the "no" column for you.
Sadly, admissions would let either of you in with good enough stats. If so, I know you'd probably do fine academically but PROFESSIONALLY I feel bad for the both of you in the long run.
Did I type the words PROFESSION all caps the entire time? Wow, must have been a complete accident.