Trying to eliminate an entire population of dangerous mice? Yeah, not that easy. They'll need a lot of poison and some very clever traps. Couldn't put the work on predators, they'd just be frozen. The poison might also be frozen. How do the mice eat? Something to think about if this continues to be a problem.

"A... cornfield. Out of nowhere. What?" That didn't make any sense at all. Why would that happen? "Was there a reason for the corn field?"

Alright. Either he's definitely absolutely nuts, this is some kind of science fiction simulation, or he's dreaming. Maybe all of the above.