Hi Me,

It's great to see you on the board!!!!
In my understanding of Korea, if you haven't got your E2 visa, then Immigration doesn't know about you. It is only immigration who needs the release letter, to release your details from the school, location and records, to transfer you to another location. The new school would ask you if you had a release paper if you told them about your previous school.

In short- You may pack up and go, BUT, what will the boss of this place do with your name? It might be worth considering where to from here.
But as you have completed 2 contracts, that makes you an awesome teacher.
Maybe you should start looking for a better position, and leave after payday, because if you give notice to your employer, you may miss some pay!
sad but true.
Beatrix