There's something in the easy, almost happy way Sif says that that bothers Cho on a very deep level. She knows her hands aren't clean. Not any more. She's got more blood and pain in her past than she can ever hope to wipe clean. But she doesn't enjoy it. She's not proud of the lives she's taken, she's proud of the ones she's saved.

So she nods, smile tight, politeness for the sake of not riling Sif up. If she's happy, she's less likely to be a problem. Hopefully also less likely to give Cho a hard time about how she works her magic.

Sansa's man comes back with a plate of cakes - tiny, dainty, feminine little things. Figures. Cho stuffs a bunch in her mouth, cheeks puffed out like a chipmunk, and works the first spell. A successful casting. No Sansa. She refolds the map, focusing on a different section, and starts again.