My understanding is that people such as doctors, teachers, lawyers are referred to as seonsang-nim. It’s like saying “Sir” or “Madam” but for specific professions/castes of people. I imagine that he is in an instructor/medical type role as a physical therapist and Potato is actually saying “sasangnim” or some variation as a more casual way of speaking. I know that for a lot of Korean students they end up saying things like, “Teacher Kim” rather thank “Mr. Kim”.
In Korea, physical therapists, along with radiographers , clinical pathologists , occupational therapists , dental hygienists , and dental technicians, are considered legal medical technicians under the Medical Service Act.
Gyosu-nim is used for specialist doctors who already have the title of professor while seonsaeng- nim is usually used for lower levels such as interns, junior doctors, nurses, resident, etc.
I believe in korean they say seonsaeng-nim to Kim Dan. The translators decided to change it as Doc Dan to emphazise that He is a medical worker. Physical therapist Dan is too mouthy and long.
Nurse Dan is wrong bc He isnt a nurse.
Is it normal in Korea to call someone "doc" even if they're not a doctor? I know dentists and phd holders like to be referred to as "doctors" and they have some good points on why they should be called one, but a PT? How is a PT a "doctor" ? It may even lead to some misunderstandings in a hospital setting