But she has to have something, or she won't stand a chance.
Isn't she (and the others) just like Ichigo in the area of the three digit fighters.
And those are all former espada, right.
So without a bankai she won't be able to beat one on her own.
And since the others are not there and will be fighting their own fights nobody will help her.
Unless someone comes to help her besides the others (like Byakuya).
Neither Ichigo, Chad, Renji or Ishida will finish their fights fast enough to help her.
Ichigo and Renji have bankai, and Ishida and Chad might be close to that level after their training.
That just leaves Rukia.
Or she doesn't have anything and is just to stupid to realize she won't stand a chance.
"For Feanor was made the mightiest in all parts of body and mind, in valour, in endurance, in beauty, in understanding, in skill, in strength and subtlety alike, of all the Children of Illuvatar, and a bright flame was in him"