Division 2, Air and Space Museum + Moon Cultist, Cheese Strat Just For Fun. Straight up this isn’t some super cool technique but it has potential due to recent changes in Escalation (won’t lose tokens on death). So start up the Air and Space Museum Escalation on whatever difficulty you can do. Now often some Moon Cultist will spawn from current event, ignore them let them chase you into mission area. In fact try getting as many of those mobs chasing you plus the mission mobs. I did this on Tier 10 with Glass Ember Engine build (I need to post this build). Here is the cheese, die or kill self once mobs are inside mission area and then immediately fast travel to mission entrance. Test this (fast travel while alive to DC and then back might lock the fence door) might work haven’t tried.
Cultist mobs will still be inside the mission area trapped and not despawn, you burn them all down and they can’t do anything. At most had 3 mobs trapped inside and Ember burned them down with help from turret too. Anyway some tactics can be made from this scenario and know I will be exploring it more like maybe getting the necromancer in there. Only reason I mention this being an Escalation is you can farm some prototype gear once mission first start because some will die, bonus. I had three prototypes in the area first time.