I just thought it'd be a good idea to exchange numbers. That's all. It'd be a little odd to simply show up without calling first, don't you think?

[She's just now gotten used to carrying hers around everywhere, partly at Hakkai's insistence. He's even made sure his number is the first one on her list in case of an emergency. Ayumu pulls it out of her skirt pocket.]

If you give me your number, I can put it in here. So we can keep in touch if you like.