If it helps, Viggo smiles when Klaus answers. But it's definitely a 'yup, I've lost it' kind of smile. Or possibly a 'yeah, this guy has lost it' smile. It's hard to tell.

He's not going to argue the point though. He's been speaking Norwegian the entire time, but it seems pointless to say so.

Instead he fishes out his wallet and pulls out his police ID, showing it to Klaus. It'll look English to him of course, but it does also state that he's part of Oslo police. And that his name is Viggo Lust. So there's a name, at least.