Since it is a Korean official passport, everyone just glances at it and wonders if it is any different from an ordinary passport? And just let it pass.
The immigration staff may have noticed it and turned a blind eye.
Or maybe it’s just that people come and go like Germany used to do.
Since it is an official passport, they may have thought that there was something important to do there.
Unlike entry, departure is easy, so you could have just skipped it.
Anyway it’s a mystery
When I arrived in Incheon and told him I was from North Korea, they thought I was joking and didn’t even talk to me.
Since it was a passport, only then did all the officials in charge come out.