"I can't tell you why," Billy said, fidgeting a little bit. If he had to snatch them and run out of the shop, he would. Would the magic shop let him run out like that? He definitely wasn't shoplifting since they were his own items but could Hermione do something to trap him here? If she did he may have to either use one of the staves or become Shazam which was counter productive. What would Korra do in a situation like this?

"I'm sorry, but I can't. I know that's not much of an answer but I just can't. But if I thought these would be better off with you, I would give them to you. I promise. I could, um, maybe let you keep them for short periods of time to study them though."