The way Strikes seem to work. You are spawned in a Public Bubble with Respawning enemies that dont seem to have a different drop rate. Then you go through 1 or 2 Dark Zones where the Enemies dont respawn and are in a limited supply. And usually you have to kill all of them before DinkleBot opens a Door. If the Dark Zones have a higher drop rate then it would pay to Kill them very very fast, so you can complete the mission, get the End Roll, and Start all over again to rekill the Dead Zone enemies.