Since he has been unable to convince Olenna to agree peacefully, Tywin goes with a threat: if Loras won't marry Cersei, he'll be named to the Kingsguard. And that will mean he'll never marry or have children and the Tyrell name will fade. And Highgarden would go to Joffrey's kids, which presumably no one really wants. As a side note, I like that no one's asking Loras to weigh in. Unlike some people (Edmure Tully), Loras is going to do his duty without whining and marry whoever Olenna tells him to. Olenna asks if Tywin would really want Joffrey guarded by someone with Loras's nocturnal tendencies, and he points out that Loras is also an extremely capable fighter who follows his vows. He holds his quill over the paper that will assign Loras to the Kingsguard. Olenna sighs and compliments Tywin: "It's a rare enough thing, a man who lives up to his reputation." She breaks the quill. So I believe Tywin wins, given that Olenna came to him with the goal of breaking up the Loras-Cersei match and now appears to have conceded. I wouldn't mind a rematch, though!
Back at the Wall, they're still climbing. This episode is named "The Climb," and I think I'm starting to guess why. As someone pounds his snow axe into the Wall, it appears to hit some kind of hidden fault line. A huge crack appears and starts enlarging. I wonder if this is a defense system that was built into the Wall. That would have been a good idea. The crack goes quite a distance horizontally and causes a huge avalanche. Ygritte falls. And so does Jon, since he's below her. Tormund grips the wall, so he and Orell are fine. But now there's a big divot taken out of the Wall, so Jon and Ygritte are dangling and can't reach the actual surface of the Wall. Orell says to cut the danglers loose. And then he remembers that he's got a knife, so he gets right to work on that. Jon starts swinging the rope, trying to get to the Wall. He does! And he's even able to dig his axe into the ice before Orell finishes cutting the rope. Ygritte falls, but Jon's got a pretty good hold on the ice, so now she's dangling below him. She gets up to his ledge. Jon looks up at Orell and Orell looks down at him. Then Ygritte and Jon start to climb again.
King's Landing. Sansa admires Loras's pin, which he prefers to call a brooch. He muses on the difference between pins and brooches, which is not really the sign of a scintillating conversation. They both awkwardly claim to be happy about the secret plans to wed. He says he's been dreaming of large weddings since he was young. The food and the tournaments seem to take precedence in his mind over the bride. And the bride's gown seems more interesting to him than the bride. Loras tells her that King's Landing is the most terrible place there is, but it's not clear if he's being sarcastic. I notice that I only wrote down things Loras said, but that's just because Sansa was kind of filling space there. She's okay at talking about weddings, but she's less good at secret plans.