[The fact that he knows of vaults at all confirms it for Roy as well, but that only makes him a little more on edge. These people from different places may be totally unknown to Roy, but he's aware of what wastelanders are capable of. Granted he's only been out there for about a week, but he saw enough to know he doesn't like it.]

...Washington D.C, guy. Take it you ain't from around there.

[It's not all that surprising, really. There's Boone, after all.]