I dont know about mice, but cats can reduce their fall damage by archieving a specific pose and thereby turning their body into a natural parachute, thus limiting terminal speed into more surviveable amounts. Which is why a fall over a short distance, like say 5m, is actually more dangerous to cats than a fall over long distances, like 20m plus. They dont have time to assume their parachute pose in the former case. They still can get injured in the later variant though, just less severely.
If this was a realistic scenario then the spider matriarch would die from fall damage. But there is nothing realistic about spiders this large in the first place. Spiders, just like insects, use an outer chitin skeleton and dont have the ability to breathe either; they simply have passive air holes which, thanks to their tiny size, is perfectly sufficient. Chitin couldnt manage to hold a large size like that together, which is why mammals have an inner skeleton of bones. And trying to breathe with nothing but air holes wouldnt work at these sizes, either. For us humans, only our outer skin layer, the epidermis, the part of the skin which doesnt have blood vessels or sensitivity etc, breathes this way.
