Keep in mind that someone pays your salary. That depends, in part, on how much money you bring to the institution. That can be from clinical care to patients, research grants, and /or tuition dollars. Despite the fact that tuition is high, the money that is available to pay faculty for teaching is very little. With this in mind, medical schools are likely to encourage faculty to bring in money through patient care and/or research (patient care is more lucrative) and do a bit of teaching on the side. It is more likely that someone with expertise in how to best teach medical students is the director of the M1 curriculum then and faculty are recruited to give a lecture or two each year on their area of specialization. So, if you are a cardiologist, you might be giving 2 lectures on cardiac physiology and maybe someone else in your department is tapped for an hour on cardiac electrophysiology. There is someone orchestrating the order in which speakers are lined up and asked to lecture and asked to submit some questions for the exam but there is no one actually teaching an entire course in physiology as you would have in college. Faculty also teach, often as "good citizenship" for a tiny amount of salary, or just for the glory of being a medical school faculty member, in clinical settings (aka "at the bedside") beginning with first year students who learn how to take a history and conduct a physical up through teaching, mentoring and supervising residents and fellows as they move through their training program and gain autonomy in the practice of medicine.
There are physicians who get masters degrees in education and learn how to design curricula, how to assess student learning, how to teach others to conduct small group sessions, give feedback, etc. These folks end up doing at least part-time supervision of instructors/lecturers often while continuing with clinical care at least some of the time.
