Politically motivated killings can't go on forever and ain't a sustainable strategy. Their macabre nature even if sanctioned from highest offices makes them despicable and revolting even to these dictators. Given hum yearning for freedom, these killings lead to more dissidents or extremists who eventually wear even most resilient dictators out.
While I appreciate Kagame's role in taking Rwanda from the deadly past; it is certain that he will fall on his sword or if he is to die in office he will have set Rwanda up for a vicious bloodbath.