I had been thinking “в Южную Корею” is the right way before I heard “в Южная Корею” in a movie and after searching I found both ways abound in examples.
UPDATE: It was a Japanese movie, 君よ憤怒の河を渉れ, dubbed by Мосфильм under the title Опасная погоня. The line can be found at https://youtu.be/P1g_uS7abmk?t=8723. In fact I had trouble understanding the whole line, which to my ears sounded like “Тоже на (?) лететь в ... спешу ...”.