If they killed us all, who would they oppress?
There is a clearly established pattern from the real world examples of Cuba, Red China, and the USSR:
1) The “useful idiots” go first — after all, their use was to bring about the revolution. Once the revolution is successful, who needs a bunch of idiots walking around?
2) Those who are not orthodox enough for whichever particular flavor of leftist orthodoxy happens to be top dog after the no longer useful idiots are dealt with. This is the “elimination of potential competitors” stage of totalitarianism.
3) Each other. A high percentage of the victims of totalitarian government violence are in the ruling clique. This is the “elimination of direct rivals and their associates” stage of totalitarian governments.
4) Another nation. An outside threat is always needed to keep the ruling clique in power and give the guys with guns and training something to focus on besides how sh-—ty their own nation is getting.