This is a rather short mission but you’ll be on the clock for it so consider a replay where you can skip the cutscenes to save yourself a little time. Head to the left of the two mission markers to find a hanging corpse, as Arthur ponders the brutality of it all he’s hit in the neck with a blow dart which knocks him out.
You’ll awake tied to a chair and being beaten repeatedly, when you get the chance, take a look at both of your hands to try and wrestle them free and then begin rocking the chair back and forth. Once you break free from your bonds, press the [Triangle]/[B] button to grapple the man and then beat him to death.
You’ll now need to follow Leon throughout the ruins, keep crouched to limit the noise your footsteps make and follow his every move until you eventually find the three workers. Activate Dead Eye right away and shoot all three of the ropes down, you’ll have to do this within 4 seconds if you want the Gold Medal.
This unfortunately has the side effect of alerting the soldiers in these ruins. Take cover and begin covering Leon where you’ll want to make use of Dead Eye to pull off headshots. The soldiers will flank from the left and right so the nearby bit of wall is the best place for cover. Once you spot the sniper up high in the center, take him out as quickly as possible or he’ll kill Arthur within seconds. Once the final soldiers fall, Leon and Arthur will escape the ruins with the workers.