[Really, Rose probably could've gotten out of the way very easily, but... she's just so baffled by how weak and pathetic that attack looked that she just kind of lets it hit her. And maybe it's just Rose's imagination, but the exhaustion she's been feeling after an earlier encounter with shadow monsters- part of the reason she went with tossing her shield instead of a rock- seems to be relieved just a bit.

Either way, though, one thing's clear.] ...I don't think your weapons are working here. [She can't help but have a small chuckle at Peridot's expense.] I really recommend you surrender- I'd hate to have to hurt a helpless opponent, but I can't let you torment the poor people here.