It probably goes without saying, but certainly for none of your core clerkships, and likely not even for an elective during 3rd year. Your best bet will be during 4th year.
My DO school allows international rotations, but there is an application process that must be submitted and approved months in advance. They even have established relationships with hospitals in SE Asia and one in sub-saharan Africa that are automatically approved and don't require a separate application process.
Depending on your school, the more difficult prospect may be finding a medical school / hospital in Korea where you want to be that is willing to take you on as a liability.
It's certainly worth exploring, but something you don't need to really worry about until after you finish 3rd year.
Get back to studying!