What’s the difference between a trainer or a medical trainer

You ask an interesting question.  When I just saw the word "trainer", I immediately wanted to know what field or industry.  The second part of your question was about medical trainers.  As a former manager trainer myself, I received assignments that required training in a classroom setting.  However, I have a friend that does health and safety training for CPR.  He often starts his training inside the classroom, teaching people what to do.  The he takes the participants outside or in different parts of the building to simulate emergency situations where CPR, etc would need to be given.  Consider typing your answer into the US Bureau of Labor Statistics site bls.gov.  It has a variety of information gathered from employers and they house job descriptions on the site.  Good luck