OOC
I think there has been a miscommunication. I am clearly not good at writing posts that are easy for people to follow the action of.
They left the car-- they are in front of the Terminal building. Sean is saying he'll wait in front of the building.
He is sending the rest of you into the arrivals lounge. Within the arrivals lounge there would no doubt be an array of coffee shops, restaurants, convenience stores, etc. for both people waiting for those who are on flights arriving (particularly in cases where those flights may have been delayed) and for those who have arrived only to find no one is there to pick them up yet.
There would be no need to buy any sort of ticket-- even if you did, the departures terminals are a entirely different building from the arrivals terminal. You'd have to walk to buildings A, B or C for a flight departure. Departures and Arrivals sections are completely separated with no overlap-- it doesn't work like a bus or train station.
In fact, because no one is waiting to board in arrivals terminals the only thing past any gates would be baggage claims. And then after getting your luggage, everyone would exit through the same gates.
All shops and restaurants would be outside said gates. So if he has already arrived, you'd no doubt find him wandering about in one of those. So the idea is meant to be that Sean will wait outside the main doors of the terminal while the rest of you check the restaurants and shops.
It was meant to be a chance for you to express which kinds of shops and such you decide to go to and how diligently you try to search for him.
As for Jubilee getting into a "supply closest"-- let's just say that the necessary materials were in the trunk of the SUV instead.