While Frost explains how she had to use the assassins to kill her son but then had to shoot the assassins to save her son, and that she disabled the Intersect to keep him from following down the rabbit hole of her loyalties and associations, and all this stuff, Chuck is calling Sarah on the phone every five seconds to bitch and bitch and bitch about his mother and try to derail the interrogation. Casey eventually shuts him down, but honestly he needs a neck-pinch for this part because he's not going to calm down. He has no reason to do so, honestly. And in any case, the new status quo is that once Alexei figures out that his men are dead, he's going to be coming straight for Castle to retrieve Frost, and that is going to get scary. In fact, already has.
Whichever one of those awful nerds brings the phone to the obvious killer lady in return for shaving his back. The other one yells at him about this, but then she pokes both of them with a syringe that makes them shut the fuck up. Her team floods into the Buy More and they start to set up for whatever assault is going to happen to get Frost back. Morgan, who is giving himself a bit of a footbath in preparation for Friday, sees this shit go down and immediately calls Chuck. Who is too busy douching it up to really pay attention until Morgan explains that Alexei is totally in the store with a bunch of guns and fantastic henches.
Casey makes all these amazing anti aircraft-looking guns come out of the ceiling of the Buy More and it's totally rad for a second, but then Alexei shuts all of that down too, because he's the best. So now they're stuck in Castle with Frost, Jeffster is hopefully being tortured to death, and Morgan is running around in a wifebeater looking very yippie-ki-yay, if I do say so myself.
"This is not a negotiation. Give me Frost or I'll kill you all, starting with the fat man and the Indian." I say let him prove it and we'll go from there. Casey ascertains that he can climb through the walls and patch into some kind of override system if they just stall Alexei long enough. And of course assuming that Agent Frost doesn't do some other fucked-up thing she's had planned from the beginning of the episode, because she loves that sort of thing usually. Well, it's kind of both: Turns out Alexei is in love with Frost. Like a big crazy Lex Luthor kind of love with her that makes him a bit of a pussycat in the grandest sense and more than a little like a blonde she-male in the specific.