Different worlds indeed. If she was just from one set of her memories she might have become concerned rather than alertly aware. But one could only spend so much time with Henry McCoy without learning that who a person is matters more than instant impressions or instinct. And nothing about Malia has ever given her cause for concern, never made her think Malia might be evil. But she would be alert. In case this wasn't Malia's doing. Or it was an she was doing too much...