Was it the fact that Margaret had Acero, much more durable than a standard Hierro? Or was it the fact that, as an Arrancar - and one capable of reaching Espada at that - her Reiatsu overwhelmed those puny blades that the Vagrant soul had fired at her? Or was it the simple fact that, through her honed instincts, Margaret was able to deflect a majority of the weapons that had been thrown at her? The blades that passed through the Negacion disintegrated on contact, for it had entered a contradiction with time and space, attempting to enter a portion of dimension that did not exist. 

"I'm not interested in eating anything at the moment. Don't think I saved you out of any particular value within you." Margaret grimaced as Marie's flying sword assault ended. "I finally found some peace and quiet around here and I didn't want it ruined by a fight."