In Guy's room, the assassin approaches him from behind and... tries to choke him. Wow, what a good assassin, going for the always messy and difficult choke hold instead of stabbing or shooting while you have a good shot from behind. That's just dumb. They fight around the room, and then the assassin throws Guy out the window. Oh, right, that's another no-fuss, no-muss way: a struggle followed by shattered glass and a broken whatever the body lands on. Which happens to be the van Chuck's sitting in. Sarah and Casey break in right then, and the room's empty (where'd the assassin go?). They tell Chuck Guy's not in his room right as Guy's bloody body slides down the windshield. Chuck says he knows.
Back at the OOSSL, Casey's talking to Jill, who can't stop crying. Chuck and Sarah are on the other side of a one-way mirror watching, and he wants to console her. Sarah tells Chuck that Jill can't know he's a spy. He's much rather her think that than that he's a stalker, but Sarah assures him Jill won't think that. Casey asks Jill why she thinks Guy might have been killed. He tells her he's in a secret CIA compound, and that they've been watching them for days because they thought Guy was involved in something shady. Jill looks through the photos they've taken of her and sees Chuck. She asks Casey if he's involved, and says he's been acting really strange. She says he's almost like a stalker. Casey tells her it's a pattern with losers to get all infatuated, and that no, Chuck's not infatuated. Jill says that Guy wasn't involved either, at least not in the way they think. He has an anti-serum for a strain of influenza used in bioweapons. It's a bioweapon that can kill a person in one hour if exposed (this will be important later). According to Jill, Guy recently learned that their company sells the influenza bioweapon, so he was going to present the research at the convention to keep the company from covering it up. She says she will have to do the presentation instead. Chuck starts banging on the glass, because it's too dangerous to let Jill do this. Jill tells Casey his window's knocking. Casey goes next door, and Chuck says Jill isn't going to the conference because it's too dangerous and the assassin will kill her. He says he's putting his foot down... gingerly. Casey says he has to look after everyone, not just whatever girl Chuck likes. Chuck appeals to Sarah and Sarah says fine, she'll give the presentation. Not exactly what he had in mind, but at least he knows Sarah can handle herself.