Sophia walks through the building, which appears to still be under construction. That's a very popular location for action scenes, you know. She finds Thomas and they hug. Say, who's the new spokesperson for the detainees in Inostranka?
Sean and Leila. And a mysterious woman with a gun. Hey, have you heard what Raymond Chandler said about storytelling? "When in doubt, have a man come through a door with a gun in his hand." I think that's what's happening here. The gun-toting woman says, "I need to know how much of your father's file you've seen." Sean says they haven't seen anything. They just found it! He offers to slide the file over to her and forget it exists. Leila is willing to get shot over it, but Sean isn't. The woman creeps forward, and then Sean disarms her. Leila grabs the gun.
Back to the rec room. Excuse me, "office." Leila and Sean are interrogating the mysterious woman, who promptly tells them she's Madeline Jackson, a journalist. Then she starts ranting about how people don't want the truth, and the lies keep the construct together and churches and consumers and blah blah blah blah blah. It ends with, "I'm not the deluded one. You are." Well, you're the one trying to keep them from reading the file. They're actively trying to become non-deluded (I guess they're trying to get luded?) and you show up waving a gun, trying to stop them. She has some valuable exposition about Leila's father, Michael Buchanan. Two years earlier, he was flying to Alaska and saw a mysterious building when he had to divert. And because he obviously knew that there wasn't supposed to be a giant government facility in the Inostranka mountain range, he started to do some research. And he found, as Madeline says, "An article I wrote on a site that I had." This site no longer exists, because they (I don't know if it's the same "they" as "They") hacked it. Or something. Madeline's theory is that Michael knew too much, "so they took him."
Sean asks for the whole story. So Madeline starts with "In 1944, an aircraft..." and goes through the whole thing. See, exposition is supposed to work with one character telling another something that they might both know, but the viewers don't. When one character tells another something that the audience already knows, it's not exposition. It's boring. Sean and Leila are skeptical about the whole story, even though it's not any more crazy than the things that have already happened to them. Madeline says the detainees are "EBEs. Extraterrestrial Biological Entities. Aliens." Why wouldn't you just say "aliens" first? Save the conspiracy jargon for your late-night call-in radio shows.