Void Fissure Missions

[cadenceContrivance]

This has probably been brought up, but I have to rant because it's so frustrating... I like to do the void fissure missions for the void traces and the prime parts to sell off, but the thing that annoys me is that some fissure missions have the mission type set to exterminate. Reactant only drops when there are enemies, therefore if someone comes in late to the mission (like myself), if there aren't enough eneimes leftover, I won't be able to open a relic. A prime example of this are fissures on Earth's exterminate, as you only have to kill a minimum of 50, and since they're all low leveled, it won't take long to clear the map out.

 

Maybe I'm wrong, maybe there's a way to get more reactant when the target kill is complete, but it's still frustrating as hell to join mid-session. Telling me to go single player instead isn't an option for me, as it is a boon to be able to select which reward you would like (which is another reason, others join mid-session too, and can't collect enough).