She lacked ability as a swords woman unable to swing the sword or perform any incredible feats with a blade.
She also lacked sufficient accuracy as well as hand eye coordination in combat to be an archer and was completely unable to use a spear effectively, always falling or getting hit by the long handle.
A pathetic existence for an individual training to be a knight that would fight on the frontline.
Rehab knew all this and yet still moved forward, still kept on trying to prove herself even though she knew that it was pointless.
It was known amongst the knight candidates that all those whom had succeeded in completely merging with the essence of the Holy Grail, would be able to have access to a special ability.