The will of the people will not always out.
Some tyrannies survive their tyrant (e.g. communist China and Cuba among many others). Some tyrannies are toppled and replaced with others (e.g. the Russian and Iranian revolutions among many others). When the people have had enough, no government can stop them, so it can be argued that all governments--including tyrannical ones--have some level of consent, however small, of the governed. Revolutions happen when, in the course of human events, a people are willing to suffer the consequences of throwing off the current tyranny.
Some caveats, though:
1. A tyranny is easier to remove, and there will be fewer consequences of that removal, if the people have not been disarmed by that tyranny.
2. If the people have been disarmed by a tyranny, they are still powerful enough to remove that tyranny. It will be much harder, and the people will suffer tremendously more in the process of removal. Therefore, the tyrannical situation will have to get much more dire for the people to believe that the political change will be well worth the tremendous suffering