So? All we have to do is send wave after wave of troops towards the killbots until they reach their inbuilt kill-limit and switch themselves off. I saw that in some sort of documentation once. I think.
Well, Musk has a point - trying to think ahead in order to prevent unwanted consequences is usually a good idea. As long as you keep in mind that this is far from perfect. And some genius or some idiot or some set of coincidences or a combination of all that will at some point trigger something that no-one could have possibly anticipated.