There is conflicting information on the web about in-transit protocols for ICN transit tours. We are arriving 0520, departing flight 2000, tour reserved for 1000 - all earlier 5 hour tours are booked. Would like to try and get an earlier tour time, come back, go airside, eat, shower, nap, etc. As I understand it, you go through security and then head upstairs PRIOR to immigration to access airside.

1 - Can we stay airside (through security, but not immigration), shower, eat and then leave airside to the main tour desk landside?

2 - Can we immediately exit through immigration, eat and hang around until 0700 and check the main tour desk for an earlier tour, if not kind of stuck landside until 1000?

3 - Possibility of earlier tour availability?

Recommendations?