The courtyard is about 40 square yards of area.
Getting higher up could give you a sight line into the courtyard over the walls.
(OC: The darkness penalties is 0 around the bonfires, -3 for areas just far enough away from the bonfires.)
There are tall buildings around, but climbing up them could be dangerous and difficult.
The building itself has been fortified mostly around the entry doors (barricades and a checkpoint) but the inside could further fortified. It is two stories tall, all the windows are boarded up with metal. The building itself seems to be solidly built since the Old World days, thick walls and tough doors. Maybe valuable stuff used to be stored inside?
No vehicles are in sight.
The slaver guards are carrying rifles and SMGs, they are armored around their limbs, torso and extremities. You can tell they are slavers by the shackles and handcuffs some of them are carrying on their belts and lying on equipment tables. There's also an empty metal cage, big enough for a human to stand in, placed in the center of the courtyard, besides a few tents and a bonfire.