You know, without being given details I would choose based solely on numbers. Kill a leader, another is elected. Kill a CEO, the next highest stock-holder steps in. I don't think there would be much chaos, or a power vacuum. We do have vice-presidents and shit. On the other hand, killing ten thousand would, in fact, probably screw up the workforce for a little while, and have a much more tragic effect. Also, if I'm omnipotent, why am I doing this? And what sort of worse consequence could there be if I chose neither?