The other party, at the Buy More: Lester is collecting money as people enter and then running around trying to stop them from having fun (i.e. stealing DVD players, not wiping their feet, playing Guitar Hero, touching merchandise). If you're this uptight, Lester, you should have had the party somewhere else. What did you think? That people would stand around drinking and touch nothing? The only legitimate complaint in all of your running around reprimanding paying customers is the stealing. Everything else is to be expected.
Mark's not surprised Dick Duffy is the bad guy, because he used to terrorize him in high school, so of course he'd now want to terrorize on a larger scale. They set up the meet outside with Dick, and then some actual Russian mobsters walk in. Chuck and Mark are oblivious, though, because Mark chooses this moment to express his regret at not coming to the feds right away instead of stealing the bomb plans. He said that because the bad guys threatened his wife, he wasn't thinking straight. Mark says he's just a guy who likes math who got this beautiful girl (really? Her?) to fall in love with him and he feels like he's dreaming. Right then Sarah walks in looking as hot as ever and Chuck looks over at her, completely in love. Seriously, Chuck and Sarah have such chemistry, it sizzles even when they're clear across the room from each other. Mark says he knows a cool guy like Agent Carmichael would never understand, but Chuck acknowledges that sometimes the nerd gets the girl. Sarah keeps walking on outside to the meeting with Dick. Who lives up to his name once again by coming onto her and even groping her. She gets mad and knocks him out. Casey comes over and they see he's just selling illegal DVDs, knockoff watches, and pot. He's small time. Back inside, Heather's telling the Russian mobsters that her husband spilled everything to the feds. She heard him talking to his handler, "some CIA badass named Carmichael." Then she adds, for effect, "Kill 'em both." So, are we to believe that Heather is the boss of these guys instead of just someone who made a deal with them? Because I am really not buying that she'd be smart enough to be the boss of anyone, other than her pathetically adoring husband.