She doubts that he can actually keep that kind of promise, but at the same time if anyone can, she figures, it would be him.

So after a moment of consideration she pulls herself up and jumps on his arm to race up there and hide in the junction of his shoulder and neck, burying as deeply into his fur as she can, a little shaking ball of fur emanating just a bit more warmth than she logically should.

She'll still hiss if he tries to reach up and pet her, but logic is overrated and clearly the world doesn't adhere to it anyway. (If she wasn't this freaked out, she might wonder why she keeps being able to see him as he is, but she's really not in a state of mind to consider such details right now.)