The particle physics community is indeed not that big so that it is definitely spread over only a few universities (especially theorists). I have checked what researchers at SKKU do (see here), and there is definitely a small overlap with what I do. However, it is sufficiently apart so that there is no surprise I don't know people working there.
I am looking forward to come back to Korea. For now, a lot of my Korean colleagues will probably all come to Lyon in France in June. I will let you know when I will travel Eastbound (the only condition is the no-quarantine one which is making it impossible to manage).