[He was kind of hoping for an answer like "oh yeah, I know exactly what caused this, here's what you have to do..." but that would be too easy, wouldn't it?

At least it doesn't seem like he'll try to stop them. Add relaxes, just a little. The shopkeeper isn't such a bad guy.]

Understood. I'll do my own research as well... whatever the cause, we'll find a way to fix it.

[... anyway, they should probably go back and finish up with those boxes. and the medicine cabinet too. but before they head out the door again where someone might overhear...]

... Thank you. Sorry if I was rude before.