Here's another opinion on what happened with Roy Horn and the tiger. Other animal experts are now saying that the tiger was trying to kill his handler and that it wasn't all an accident involving an otherwise benevolent animal trying to "help" Roy.
I'm not sure how much the difference matters or if both views aren't just a matter of humans pretending they know what's going on in an animal's mind. Seems to me the danger presented by a tiger like that is the same no matter what was on the critter's mind. It can hurt someone trying to help them just as it can trying to hurt them.