Carpe Diem (Side Quest)
The quest trigger for this is inside the commander's office in the Kyrenaika Roman Citadel.
Follow up by locating this freedom fighter on the main road to Cyrene.
It's a small post, with half a dozen guards clustered about.
Enemy forces are thick enough that sneaking by is no option, but try to maintain stealth as long as possible while using the fences and shrubs for cover.
Interestingly, even the cages act as full cover.
When the hostiles are down, free the prisoners from their cages.
Then free Apate from the chopping block.
Follow her up into the hills to discuss your next move.
This turns out to be an assault on Prasinos Outpost.
It is possible to just ambush Severus himself at night, but attacking the outpost allows you to complete the location as well. Scan for an overview of where things are, with the treasures in tents on the west and east sides of the camp.
Start by scaling the outer wall, up to the twin guard towers over the gate.
Once you're inside, it's only a matter of time before the rebels attack, so start by sniping Severus, to make sure he doesn't get lost in the confusion.
Do the same to the captain and commander, for the same reason. Snipe anyone else who looks like they need it (there are ammo refills up here), then take to the turret for some more indiscriminate killing).
It will run out of ammo eventually, so mop up any survivors the old fashioned way. When the camp is clear, visit the two treasure locations, that one tent on the eastern side, where the treasure is in a small carbon crystal box on the table,
and one in that tent on the western side, where the treasure is in a large red chest.
Snagging that completes the location.
Confirm Severus' death to complete the quest.
There are prisoners in camp that can be freed as well, but watch out for hostiles mixed in with them.