once you start you cant stop and you have to be able to make decisive impact before they get their shit together properly. And anyone doing anything would have to sacrifice everything they have since this wouldnt be tied up for long time if ever.
Only way to do it even a little safely would be if tons of other people rise up too. If they kill singular person or group it will just increase their control as rest will fear even more. If they start killing everyone then it will reduce their control as people will see that if they submit they will die. This is also why apathy and hopelessness is one of the strongest chains they have on our necks.