they didnt appear in S1. In the episode, Cha Eun Jae mentioned how KDJ was popular for being hard headed and stubborn.…
No i don't think so. eunjae says to dongjin.... "He won't remember us right? That happened ages ago".... Then again in the staff room she was worried that does he remember or not and later one of the doctor said that woojin and dongjin got into a big fight as residents that's why i think something happened in the past they might give us some kind of background story .
The conflict between dongju and woojin made today's ep even more thrilling. I hope they keep having this clash of opinions before finally reconciling because that will make the upcoming episodes even more entertaining.
Kang dongju may be harsh but he is not someone to be taken lightly. He is smart and capable of making right decisions even under extreme pressure. I liked it that he came off strong in today's ep.
4 
7 
1 
they might give us some kind of background story .