Fortunately for us, you can't kill someone with a CPU cycle. You need to use a servo for that. Which, while quick, are far from instant, and will always be limited by basic physics like thermal management.

Urgh, yes, that's so annoying. Skynet drones won't pepper the ground behind the hero with bullets while flying low and slow, they'll land every shot on target in milliseconds, before any human even sensed there was a threat. And they won't have a standards-compliant USB port to take over control either.

The only real question is whether the machines think one bullet to the head is most efficient use of resources, one bullet per organ, or an equivalent mass of non-depleted (they don't care about radiation, the biosphere is not their problem) uranium to the target biomass.

It should be obvious that a psychopathic human is different from a computer inside a killer drone.