Oh well i havent read the manga lol im taking my observations from the anime. Like, remember how before the other zombies acted before they woke up? They were barely aware of their surroundings, while Tae can understand speech and knows who people are, and she knows her name. She also has a lot of bandages on her body, including on her head (not as many as Ai but still, she (Ai) was literally burnt to a crisp so-)