The wolf is actually a bit stunned that the dog can speak in words he understands, but he doesn't try to question that fact for long, making his way even faster along the rope, and literally flying over the floor, the vine's springiness allowing him to vault a good way with each handoverhand movement, and looking ahead he swings himself around, causing the vine to twirl and then leaping him onto the shelf, which is literally at the top of the wall of the castle, which he doubts even the dog can get to, especially since he sees a bag that his nose tells him is full of dog food. The giant would have kept such a thing out of the dog's reach, to keep him from eatting it all at once. At the same time it gives him an idea and he starts to try to push it over, to spill the contents of the bag on the floor as a distraction.