Killing the tiger that killed an employee

Last week there was a human error and unfortunately a tiger killed an employee at the Biblical Zoo.
According to simple halacha, would the tiger have to be killed? The Rambam emphasizes that the halacha applies not only to a bull but to any animal that has been killed, but I have a hard time with that, especially since we are in a generation where we no longer see any interest in all this revenge, and overall the animal did what it was intended to do and there was no change on its part (the worker’s mother was interviewed and said, “Why would they kill the tiger?”)