if he will really turn evil, donny or some other nice guy will probably die. but i'm not really sure because he doesn't hold much resentment towards the holy knights after grandpa's death (even though grandpa was the only person he knew and loved), let alone the world. maybe betrayal or some...
For those who are curious about Seoul Metro map just check out the official site:
http://www.seoulmetro.co.kr/en/cyberStation.do
Chungmuro is somewhere in the middle