It may take Morgoth attacking him in his own room, to almost break Titus, but the mere idea of the same thing occurring (she doesn't understand it's not really comparable) terrifies her.

"We must do something, Titus. I'll have to ask Dr. Muraki how to keep them out." After that perfectly reasonable suggestion, she asks, as though she said nothing at all, or nothing of note. "What do we do?"