Not exactly EMS q's, but popular interview q's anyway
I don't know much about specific interview questions for ems'ers (as I'm going in for my own first interview soon!) but I did study management in college (business minor) and I'm sure some things are universal.
Most of the top 50 questions asked in interviews relate to how you see yourself, for example, are you a go-getter or do you need a lot of supervision to do your job.
Others relate to how valuable an asset you're going to be, this brings in the questions like: where do you see yourself in 5 years, or what are your weaknesses. The trick to these is to keep the answers vaguely specific, oxymoron I know, but stay with me.

"In five years time, I see myself doing my job to the best of my abilities. I see myself learning how to work in this environment and actively working to make my workplace better every day." There are no specifics but you're not beating around the bushes either. If you hate the job for whatever reason and leave before the five years are up, it's not like you didn't give it a good go.
The "what are you weaknesses" question is a little more tricky. That's the one where you're supposed to flip your negative into a positive. Like: "I'm kind of a work-a-holic, but I know that a good work-life balance is essential in this job. I think working a lot now gives me a better foundation for those tough calls that are going to happen in the future, and I know I'll gain a better footing of how to leave work at work once I settle into this job."
Know yourself also, do you tend to get really nervous and shake during interviews? If so, make sure your foot isn't tapping, or your not jingling your keys in your pocket during the whole interview. I tend to talk really fast when I'm nervous, so I make sure I take a deep breath before answering any questions asked of me.
I hope these help at least a little! I'm in the same boat you are, waiting for that (successful) first interview!!