...while at the Trident, Volkoff shows Sarah a picture of Casey and asks if she ran into him at Seabrook. Wisely sensing Volkoff knows all about Casey, Sarah says she used Casey's loyalty to her to aid her errand, which Volkoff appreciates, but goes on that to prove the truth of her statement, he posed as her and summoned Casey there -- so Sarah could kill him. Sarah doesn't flinch as she takes the proffered gun, but gets some good news when he sends Mary with her, although that's tempered by the fact that he's tapped into the security-camera feed on his phone, so he's going to be watching, too. Volkoff smiles big and tells her to have fun with it, and seriously, I really kind of love Timothy Dalton now.
As they take the stairs up, presumably to make it look like Sarah wants to surprise Casey, Sarah wonders how she's supposed to make the fight look real with all the cameras around, and Mary doesn't have a solution, but hands her the Hydra piece to give to Casey should she get the opportunity. Sarah says she will, and asks Mary to buy her some time should Volkoff come up there. They then reach the appointed floor, which seems like it's under heavy construction, and Mary hangs back so Casey won't see her...
...while back at the apartment, Chuck is pacing, and then declares his intention to go to Castle to try to hack into Casey's phone, but Morgan sighs and gives Chuck Casey's location, explaining that his prying eyes caught the address. Okay, I may have complained about the show stretching the limits of credulity, but Morgan as Eagle-Eyed Nosy Guy I can definitely buy. Morgan then talks a bit more before he realizes that Chuck is already gone. Yeah, that'll happen.
Sarah pauses near Casey's location to take stock, and sees her answer in the form of some loose paint cans on the floor. Gun drawn, she moves into a nearby camera's view and heads toward Casey, who's got his back to her, but "accidentally" taps one of the cans, which prompts him to swing around and knock the gun out of her hand before he even realizes who it is. He draws his own gun and asks what she's doing, but she in turn knocks his piece away and slugs him. As Volkoff watches, Casey and Sarah get tangled up, which affords the latter the opportunity to explain the situation in brief, rushed words. She tells him to follow her lead, and then slugs him in the face. I'll have to remember that one.