The Leo was probably concerned about the repercussion of firing his weapon.
Political correctness has eliminated the argument "he needed killing", and the officer probably chose the politically correct and safest thing to do.
Political correctness has also put more regard in the life of an animal than the life of a human. Just look at the Mary Winkler case, then the Mike Vick case.
We now live in a bizarro world.
Gentlemen, at all times, be prepared to defend yourselves.