[Senkusha]

In episodes nine and ten in A's, how did Nanoha's two friends Arisa and Suzuka get trapped inside the Barrier when the Book of Darkness was fighting Nanoha and Fate?  They aren't mages, or at least identified as any sort of mages, so why would they remain in a Barrier, when all other moral beings, and some property, like cars vanish.  Did I miss something somewhere?