I guess some people have never been faced with a spooked cow?

A tranquiliser doesn't work straight away and the effect of the dart hitting home usually makes an animal take off like a........... mad cow. In "the wild" or in farmland that may be OK up to a point but the animal has to be "tracked" until it finally collapses.

In a built up area, a cow which is already spooked will react wildly and when it does, it's bound to "hit" something or someone.

In all the circumstances, they did the right thing.