Peace corps has a few very specific programs for EMTs which mostly involve education. HIV/Aids/STDs etc.. Or disaster coordination ie who has a ladder and who has rope in the village. Your skills will definetly be used by people in your village if you get a remote assignement. People will look to you for guidence during medical emergencies. An EMT is always valuable to people in less fortunate areas..
you can't "be an EMT" in the peace corps. you can use your years of medical experience to become a PCV in the health and sanitation sector which means you will be working at a birthing clinic or a rural/city hospital. you could be doing PEPFAR HIV/AIDS education and training. however any 'emergency' you run into out there you will be less than helpful. depending on what country you get posted to, are you urban or rural? there are no resources. you are not an EMT. you are a PCV w/ a mild medical background in a country with no definitive care w/ people whose medical problems are far over your head. you can rush a MVC victim to a hospital but they will just be put in a corner to die.
safety in the peace corps is based on prevention. don't get hurt and you will be fine. you're not going to be the 'emergency squad leader' for your village. odds are the locals who have lived there for generations can smell a sand storm/tsunami/tidal wave/hurricane before you can say what. big secret : you're not there to school them; they're gonna school you.