It's possible, perhaps, that Shrike is also just a little bit curious about this fellow who claims to know his younger self. Maybe. He's not admitting to anything, at least. At least he made clear that he was accepting an offer of hospitality, in any case; his own dislike of being indebted to people aside, you'd be amazed at the kinds of favors people will try to trick out of someone as highly-placed as a court wizard. Especially one who undoubtedly has his monarch's ear.

"Good food by a person's standards, or a rat's?"

Is he asking that seriously? Just joking? Maybe being sarcastic?

... actually he just blurted that out before he could catch himself. Oops.