I love the circus. I used to buy front row seats so I could smell the elephants as they went by. I did worry a bit when animals that big were mere feet away, but nothing bad happened. The tigers won't be in the parade, but I used to go out back where the cages were and stick my finger in to touch the tiger's fur. I still have all my fingers.
As far as danger, I would think the elephants would be first, and a cc weapon won't do anything. The next danger is an trapeze artist falling on you. Enjoy. A little fear is part of the excitement.
Shooting in a crowded arena wouldn't be a good idea.