Please don't do any EC simply because it might look good on application. Not fair to yourself, and certainly your (potential) patients you may care for as an EMT deserve better than that.
If you pursue ECs to expand your horizons, they interest you or you think you can contribute to the field, I'd bet you'll find that the good-looking application will take care of itself.
I must disagree with Willow18. For being an entry-level position available to pre-meds, you get plenty of direct patient care experience. Sorry, but following a doctor around, pipetting and alloquoting samples in a lab or passing dinner trays in a nursing home can't compare to what you can see and do in an emergency department or on an ambulance.
Also, EMTs are employed in many capacities other than ambulances. Others have mentioned ERs, but also large public venues, jails, private corporations and many others hire EMTs. It also opens the door for volunteering with first responder agencies.
For many, the EMT is a starting place. You could go on to obtain paramedic certification (and really expand your knowledge, skills, responsibility and autonomy) or other allied health positions.
Forgive the cheesy metaphor, but medical school is a city you can reach by taking one of many different roads. This is one that has worked for others, and the only way you'll know is if you explore it.