I'm not sure what good flying would have done considering they are inside the book, which might equal to being inside limited space. I was also thinking of the black blood during the combat but I doubt it would have mattered in the end, especially since she can't use it as effectively as Crona.
I have to admit that it was a bit annoying she was already giving up and then won simply out of luck. It would have been far more stylish if she had been ready to fight till the end, despite not having a chance, and then get saved by sheer luck. Even more stupid was how she actually tried to tell Giriko to stop fighting in order to save himself instead of coaxing him to proceed and thus doom himself.