User blog comment:IamJakuhoRaikoben/Chapter 457: Naked Battle, Review./@comment-4999650-20151019120400/@comment-7418318-20151019185702

Now you're really going off into imagination land here.

Brandish is still a Human being. A dagger to the heart or a slit throat is just as lethal to her as to anyone else, so she can't just go to sleep before Lucy... well she probably can because Lucy wouldn't kill her in cold blood in her sleep, but that's beside the point... and not something that Brandish would know about Lucy in the first place, so it's doubly beside the point.