Although Asuka listened to the suggestion, she clearly didn't seem to like it.  Revenge was a terrible motive for killing, one that had come up with a number of horror stories like Yurei.  She didn't want to become a crazy slayer who couldn't handle anything but death and destruction.  It was much more important to her to stop the threats, and she'd be just as happy to defend people or to lock the evils away somewhere so that they couldn't hurt anyone.<br/><br/>"Why do different types of Noise have different weaknesses?"  Perhaps it was a silly question, but if she wanted to understand, it was important.