Ooooookay. She might be more convinced if she hasn't already seen Dipper be evasive. This isn't the first time should have had to chase him for answers.

She makes a noise, a little "mmmhmm" from the back of her throat. The kind of noise that someone makes when they don't quite believe the person she's talking to is telling the truth but also knows that, yeah, this time and place is the exact wrong one to call him on it.

"Well, OK...Whatever it is, don't let it distract-"

Of all the world's phrases did you hear that is the worst phrase to employ in a zombie scenario. So she listens. And listens. And strains to listen.

"...I don't hear anything."