Admittedly, it wasn't the fact that she threatened to jump on him that woke him up. Rather, it was the fact that she threatened to withdraw his ramen noodles if he didn't move. Soon enough, he was jumping up in fear of that, looking around through squinted eyes that hadn't yet adjusted to the sunlight dripping through the door. After this Gaara was able to withdraw his sand quickly enough, though it had actually looked like there had been a chance he would have actually used it to hurt Naruto. He did tend to be rather aggressive as it were anyway, but it was enough to scare Naruto along with the ramen comments.