(What I would like to say at this point, and can't, is that he could also be thinking that having Blair on your side when you're going up against Willa is an excellent move, because Blair will fuck her up as collateral damage to whatever scheme she ends up perpetrating. You could just aim her at a target just past Willa, and the vector of her destruction would slay Willa in her wake. But while this script is smarter than the last several, it's still not there.)
"Oh, a party where you two are guests? Perfect. Brimming with young men who are not socially astute enough to fear the length of the Bass arm..." (Ew.) "Now I'll need a disguise if I'm to blend in. Perhaps Vanessa can loan me a serape?" (Perfection. Well done.)
Now that he's ruined their reunion, Rufus reverts to sweetheartedness all about how she shouldn't let his shit with Will get in the way of her relationship with him. Um, except for how you just did exactly that, loser. S doesn't notice how ridiculous Rufus is being -- the white noise of his constantly fucking everything up -- and says she won't let Rufus's irrelevant bullshit interfere with her life on any level. Only the way she says it, it's like she's doing him a favor and not totally dissing his entire bullshit personality. "Right now I just need to keep things about my mom, think about what's best for her," says Serena, which is the warning flag Rufus can't see, because obviously the medical issues trump all the whining Rufus could ever... There we go. Will just called Lily, in the time it took her husband and daughter to get home, having coincidentally received the test results, which are not good.
Chuck's almost impressed by Blair's field trip to Brooklyn, to an "art party" no less, because that shows commitment to destroying everything that means anything. He offers some money to somebody, this part I didn't understand so well, but the point is that of course the fatwa is all too real. Nate comes home, and of course Chuck immediately starts trying to pour alcohol down his throat, because the seduction must begin. Nate pretends to be bitchy about Chuck whoring out Blair, but Chuck says he's very sad and sorry, and then embarrassingly enough goes, "After all these years, you can't see through one of my smokescreens?"