What types of things do you do as an EMT? (I'm just curious.)
I think it's great that you love being involved. Why don't you just follow your heart and do wherever it takes you? This will give you more meaningful experiences than comparing yourself to others. What you should also consider is that during an interview or personal statement, you may have to draw from experiences. For example, if you've been a club's errand bitch - you won't have a lot to say about what you did/felt/experienced/learned/liked. With that said, it sounds like you are on the right track though. awesome.
At first it sounded like you were doing things for the sake of putting them on your Dental application. I know some people who do this for med school or law school or whatever.. I hate it.