Thankfully, he made it to the top without incident; simply flashing his Prefect badge at Mrs. Norris made her scamper away with a disappointed hiss, and he did not see Filch. (Though he did have an explanation prepared for the eventuality: He was delivering telescopes to Professor Sinistra, and could probably back up that assertion by reaching into the crate and Transfiguring a pillow into a telescope to show the caretaker. It was for this reason that he was wearing his dragonhide gloves.)