...a snow leopard that was in the zoo and when the shit hit the fan the keepers let all the animals out and you start out in with all these other zoo animals loose around friend and foe.
Merely agreeing with your idea of having an ingame zoo, I imagined someone snatched a pair or two to partake in some gruesome experiment with mutagens, electroshocks and mutilation, essentially all the wrong things. For the sake of the experiment, they even had an arcane device plugged in to try and understand better what's gonna be happening to those poor beasts; you get to have a first person experience with just plugging in, Matrix-like. Now, the quest can be more interesting, and the character can hack the system, slide open the bars and unleash the predators to deal with their captors. Furthermore, he can coordinate the actions of the few besides him, as to try and finish the mission more efficiently, ensuring the outcome without casualties. After a fierce battle, the beast you're playing with can step on a pressure plate and release himself along with the others into the wild, leaving a door to an unknown science facility widely open. A pack of animals runs free, you plug out of the system having successfuly completed a task, only to try and locate the hidden location.
In a nutshell, can you agree, your idea with a little twist in the plot. I dig it as an interesting one.