She's glad to see Gabriel, really she is, but now he's just indulging Peter's irrational fears by making a show of attacking the Minotaur, and the dream isn't exactly putting her in a good mood. The appearance of the rather familiar blade surprises her for a moment, but she quickly recovers to peevishly repeat "It isn't real!". Can everyone just stop being ridiculous worrying about the stupid immaterial Minotaur and start worrying about the fact that the rift has created a dream from either her or the Doctor's memories without either of them noticing the mental invasion?

But clearly that isn't going to happen while there's a monster to play with and/or hide behind her from, and she waves a hand dismissively, adding in exasperation, "Cut its head off, by all means."