As an EMT you work on ambulances and medical transport vans. Providers at any level have the opportunity to work in many interesting situations. There are volunteer and paid first aid teams at sporting events, concerts and large venue gatherings, casinos, shopping malls and even cruise ships. Many larger corporations use EMTs for quick response. Bigger manufacturing plants and industrial settings such as oil refineries and off-shore oil rigs utilize emergency medical personnel.
Some hospitals allow registered or certified EMTs to work in emergency departments.
There are administrative positions as well which might include working for a service provider in the office with billing and public relations. I have also heard of insurance companies using folks with medical backgrounds in claims departments because of familiarity with the situations being billed. Most common is the ambulance response. How each respond is different as well. Another system is a tiered response.