Ok this is all helping. I am unsure about credit cards because don't you have to start making payments immediately unlike student loans where you can start payments after you graduate and are working?
DO NOT go with the credit card option unless absolutely necessary. There are those "zero interest for 12 month gimmicks", but I'd only RISK going with that IF you can guarantee you can pay the whole thing off within that time span. You don't want to drown in the crazy interest rates of credit cards. Sorry if I sound a bit angry, but it's something I'm very adamant/passionate about--I'm vehemently opposed to carrying a balance on a credit card from month to month.
That being said, I would suggest you try to get a job to accumulate enough savings to pay it off or use student loan money (assuming you have extra) to pay for your expenses. If you're not economically disadvantaged to the point of qualifying for a fee waiver, but not economically well off to the point where you can pay for all of these costs with the money you do have, it can be very tough to pay for the transportation, clothing, food, and living costs associated with an interview for medical school.
Depending on how many schools you apply to, keep in mind that AMCAS fees and secondary fees will be a couple thousand dollars. My 30 schools cost me nearly $4000 in paperwork alone. Consider that flights will be around 300-400 round trip, hotels will average you about $100/night, and food is about $10/meal. Granted, these are rough estimates that are probably on the higher side, but for the purposes of preventing underestimation of expenses, that's what I wanted to provide.
There are plenty of ways that you can reduce some of these costs--picking extra cheap flights, choosing to take ground transportation, staying with a host instead of a hotel, eating extra cheap food, etc.
Best of luck to you!