Naminé yelps as she actually does slip down, the shingles beneath her feet giving way and causing her to slide several feet down the roof. Luckily she was higher up than Natalia-- it gives her the extra second to dig her feet in and force herself to come to a stop. But now she's right on the edge, with her bow several feet away, and the Buer heading back for them.

It's a choice between climbing up to higher ground or trying to reach for her bow. But with the monster approaching so swiftly, there's no choice but to try and stop it, and so she goes for the third option. Naminé flings a large bit of shingle at it at an attempt to slow it down, hoping that it gives Natalia and Mary the time to reload.