Incheon International Airport: Problem with immigration stamp

I just arrived in incheon international airport from LAX earlier today and did not know how to get to the departure area. Hence, I went to the immigration area and got my passport stamped because i thought that that was the way to the departure are. What i didnt know was that that stamp meant that i can no longer go out of the airport. Is there a way that The stamp gets voided so that i can get another one? I really wanted to try the local transit tour since i have a long layover here.

Thank you in advance!

Best Answer

After asking the information desk a couple of times (yes, a couple of times with different information officers till i found someone whose english is good enough), they told me that there is no way for me to go outside anymore.