One of my girls was a high, high energy cat and her zoomies were epic. She did not stop at walls and her favorite up high place to go was the top of doors. She could make the leap to these narrow perches from just about anywhere and never hurt herself going up or getting down. As previously posted cats are very aware of their abilities. How they can get hurt however is by knocking things over when they make a big leap. So you might want to find a way to anchor his cat tree to the wall or floor.