[Even a small touch like that helps a little, and he gives the Doctor a small, grateful look before taking a breath.]

There's a lab that lets out into the shop. At least, I think it does. I'm fairly sure I went through the shop before I wound up out here.

[Admittedly, he might have been somewhat out of it at the time, but he's fairly certain he remembers passing through there at some point after leaving the lab.]