When Thom and Gizmo come home, Mary Ann does something very strange.

She ignores them, at least until Thom or Gizmo speak up or step directly in front of her. Normally, she would have called a welcome home out to them when they entered the door.

She's just gotten so used to using this new ability of her to sense life patterns that she just isn't paying as much attention to her surroundings with her other senses any more, at least not to detect people moving around her own house. Sure, she's heard the sounds, but her mind has filed them away as probably the wind or something tipping over.