Based on the way it's operating, the party in power in Burundi seems to be evolving toward a one-party state. The party wants complete control, and it's becoming authoritarianism, which is what a system is called when the leader decides and the rest follow. Any voice that diverges from the leader's is to be silenced permanently. If the person isn't killed, they flee.
If you consult the statistics in Canada, you will see that even among the most ardent servants of the Burundian government, such as diplomats and their staff, many have left the country and have requested asylum in Canada. Even some former ministers have done so.
We won't get into their story, because it's personal, but you will see that discordant voices do exist. If they aren't killed, they have to find a way out of the country.