I was not allowed in the audition room with her, but I could hear some of it through the door, and as far as I can tell, she did great (albeit a bit quietly at the beginning of her song, because she was out of breath from her monologue).
Her monologue was this scene from Doctor Who: The Pandorica Opens. She did not attempt the accent. And that's a good thing; natural mimic she may be, but not for an entire speech full of shouting at the assorted baddies in this scene. But I think the fact that she knows the scene very well, and the fact that she's a Whovian who knows her audience (the choreographer for the play in question is a Whovian as well) probably helped. She wore a hat and carried her sonic screwdriver as well.
And then she changed her hat to a wolf-head-shaped hood she has from Great Wolf Lodge, and she performed the last verse of "I Know Things Now" from Into the Woods. This is the song that Little Red Riding Hood sings after her encounter with the Big Bad Wolf... and it's his pelt she's wearing in the play and the movie.