Apparently the cat was so agitated it jumped the moat. An act of super-strength that was not anticipated. No doors left open.
Almost like the 130-pound mother lifting a vehicle off her son trapped underneath - extraordinary circumstances leading to extraordinary power. If an animal was provoked to the point of blind rage, perhaps it could exceed the parameters designed to enclose it under ordinary circumstances. I believe there are signs posted in most zoos for this reason - "Do not tease the animals."