Asia - Seoul City Tour w/flight thru ICN?

Hello,
I'm looking at flying from the US (US Citizen) to HKG via ICN. If I arrive at ICN at 4:50am and depart 9:10am, is that enough time to take a quick city tour? I do not want to rent a car or spend significant amounts of money, nor do I want a Korean visa. I looked at ICN website and it mentions 2-hr tours of areas near ICN and looked like all one needed was a boarding pass & passport.
Is this a good idea? Is this feasible? Do I have enough time? PS: Don't know any Korean...never been to Korea.
Thanks!

Not enough time to visit Seoul (which is 90-120 minutes travel each way). 4 hours is probably enough time to visit Incheon City, but as you arrive so early I dont think much will be open and probably no tours at that hour.

ICN airport is quite modern and has good lounges (assuming you can access these) to while away the transit.

What about transit tour? on ICN website:
Airport → Ulwangri Beach → Yeongjong Fish Market → Yonggungsa(Temple) → Airport
Ah, maybe I'll just give up trying to see Korea since my connection time is too short.

It's probably not very practical. By the time you clear customs in ICN, drive about 45 minutes to an hour to 'downtown' then back to the airport, clearing security, etc ... doesn't really seem feasible. If you weren't leaving until 3 or 4pm then you might be able to actually enjoy some of the sights (Palaces, markets, museums...) Now, maybe if there was something to see closer to the airport? Just a thought.

DD

If you want to experience some Korean life and are preapared to use Korean (or sign language) to make yourself understood, "Airport New Town" housing the airport area workers is a short bus or taxi ride from the terminal. There are several 24h restaurants offering typical Korean fare and you would most likely find merry Korean gents having a few cold ones or Soju after their nightshift at the Airport. You can probably also find a Korean Sauna including hot and cold baths, showers etc. there, but there is also a modest one in the Airport basement and a luxury Spa at the Hyatt.

As for any tours, it's just not worth it. The areas surrounding the Airport are more or less industrial wasteland.