I just cannot believe that so many people, especially on an Industry Forum, cannot understand.
The dog's cage was NOT loaded properly.
During the flight, the dog managed to eat his way out of the cage, and eat a lot of the cargo lining etc.
He also managed to release the internal door handle by pushing on it, this is the handle that most of you do not even know about.
Now OBVIOUSLY the door would NOT open anyway while the Aircraft was pressurised
and I guess the dog moved away from the door.
However after landing, AND LONG BEFORE THE GATE, with the door handle already released, the door opened enough for the dog to jump out, which he DID, and was then seen by many people running alongside the Aircraft..........
Which part don't you understand?