Oh crap. I’m pretty sure Grace is referencing an earlier comic in which “corny” was defined for her, but I can’t remember which one it was.
Uh... er... um... 
THAT ONE! Yayyyyyy
In retrospect, it’s a bit odd that Mr. Verres himself went undercover, but I’m sure I could come up with barrels of excuses for why it had to be him. It’s totally reasonable that he had some sort expertise / level of clearance regarding certain... THINGS that prevented the use of other potential candidates.