If he'd been home Jimmy might have been tempted to just leave it there. It didn't look like it was doing any harm. But since this was his host family's house, he felt like he had to do something.

He leaves for a moment to rummage through the room, and returns with an old shoebox and a piece of cheese left over from his lunchbag. Mice liked cheese right? And if he could get it into the box then he could just take it outside.

He sets the cheese in the box and sets it up next to the wardrobe, then backs up to see what happens.