[Realistically, he knows all these things about Clarke himself, but it's good to have an outside confirmation too - even if it is his sister, but doesn't that make it better? Especially with the way she'd stopped letting him get away with his bullshit.]

[He offers her a small grateful grin, but it doesn't quite reach his eyes.] I know. I know, thanks O. Nothing happened the last time we were out for a week. We'll make sure it repeats the same way.