Dallas Zoo Gorilla's 'freakish' escape still puzzling zoo officials

It will be interesting to know the outcome of the investigation of how the gorilla escaped . Can you keep an eye on the source , Sim ?
As I have a keen interest in zoo layout and enclosure design this is of great interest . Most large US city zoos contract specialised companies to design the exhibits , especially ones that contain (?) large primates , elephants and other "intelligent " species to reduce stress and boredom . One such company that has been contracted by Dallas zoo in the past is ZOOLEX .
Perhaps that it was just as well it was a gorilla that escaped rather than , say , a tiger , otherwise there would have been deaths at the zoo . Too bad that the gorilla was shot . ( There isnt exactly a surplus of gorillas left in the world ) Although I am not privvy to the situation there , I still wonder why someone couldnt fired tranquillisers instead of bullets .
It comes back to the question of what resources do the police/other emergency personnel have , with dealing with potentially dangerous animals on the loose .( Like the fire at NSW reptile farm -- there would have been alot of hot angry venomous snakes that someone would have to have dealt with ) Is there any official policy for those sort of situations in Australia ?