That's a curious word. So it's got nothing to do with going unde...
Walter: That's a curious word. So it's got nothing to do with going underwater?
Astrid: No. "unsub" stands for unidentified subject.
Walter: Actually, it should more logically mean going above water.
Peter: And still no.
Walter: I certainly hope we find him. (whispering to Peter) Who we looking for?