Layover in Seattle

We're stuck here at the Seattle airport for two hours, the flight in was on a to tiny prop plane, with shit seats. The airport here is kinda cool, we had to take a subway train to the gates. I'm not sure why the terminal was within walking distance. Our flight to Reykjavik leaves at 430 and we don't land until 6am, it's supposed to be only 7 and a half hours. We're hoping it isn't a full flight.