As we see the canoe go out into the river, we hear a voice say, "King's Landing will fall an hour after Stannis lands his force. It's not too late for King Joffrey and Cersei and the court to ride west to safety." It's one of Tywin's advisors, so obviously Tywin thinks it's stupid. He doesn't like the idea of giving up the Iron Throne even for a moment, because if you can't hold it, you don't deserve it. In his opinion, Lannisters stand and fight. Anyway, Stannis is two days out and the wolf is at his door. The "wolf" would be Robb's army. I guess he gets to be "the wolf" instead of "the cub" or "the whelp" or whatever condescending reference to his youth Tywin's been using recently. The scouts say Robb is too far north to attack them safely, but Tywin is skeptical of his scouts' accuracy. Besides: "He's a boy and he's never lost a battle. He'll risk anything at any time. Because he doesn't know enough to be afraid. We'll ride at nightfall. I want a full night's march before he knows we're on the move." So the new plan is for Tywin to leave Harrenhal and do some attacking of his own. He wants the Mountain to stay behind and clean up the Brotherhood. I really like that they haven't explained what the deal is with the Brotherhood. It's just some local resistance they need to clean up and that's all we need to know. He leaves Arya in the Mountain's service. He tells her not to let the Mountain drink too much, but I can't imagine what she's supposed to do about it. He's at least three times her size, so it's not like she can just refuse to bring him wine. She thinks. In close-up.
Then Arya walks around in the Harrenhal courtyard, past a very well stocked gallows. They're hanging six or seven people at a time in here. Some mean guys -- Jaqen's former fellow prisoners, Rorge and Biter -- won't tell her where Jaqen is and one of them threatens to fuck her. Thanks for that, show. They're called away from their important child-threatening to get ready to ride out with Tywin.