It shouldn't be RNG. Just have a set objective to get it to spawn. 1 rank reset maybe? Chaperone, ace and wish ender don't have any crappy RNG like that and they're exotic quests. They're proof that exotic quests don't need the extra grind to get them in the first place, let alone have a miniscule chance for the required enemy to spawn as well as a win condition when gambit is designed to help the losing team gain the lead and win. IT DOESN'T WORK!