Mission 08: Not The Pizza Guy
Objective: Climb to meet Jordi on the patio deck
As the mission starts, you'll see the Gorman Heights building just ahead. Run up to it and climb the small flower garden and continue upwards until you join Jordi on the deck.
Objective: Infiltrate the rail yard
After hearing Jordi's plan, drop back down to the ground and cross the small stretch of water to the rail yard on the other side (you can use the boat or just swim across if you like). An unlocked gate will be at the south end of the fence that allows you to get inside without being seen.
Objective: Interrogate the fixer boss
One point I will raise about this section is that the more guys you kill in stealth now, the less you will have to deal with afterwards (yes there will be a shootout here shortly, no matter how stealthy you are). You can distract guards (with your phone or lures) to have them picked off by Jordi's sniper rifle or just take them out yourself with a silenced pistol. Take them all out if you can but avoid risking detection (kill them in darkness away from other enemies to avoid spooking the rest) as if they call in reinforcements, you just wasted your time.
To open the door to the boss (it's locked with an access panel), it is almost directly opposite the boss's door (objective marker) on the other side of the yard and can be unlocked via camera or phone. Once the door is unlocked, head inside to confront the boss (grabbing the audio log here if you want).
Objective: Kill all fixers or escape
After your little "discussion," head back to the gate you came in by and grab the AK-47 to add it to your weapon collection. As you do, Jordi will call to inform you that the shit has hit the fan and a large group of fixers are heading your way. As soon as you walk through the gate, the game will save a checkpoint and lock the gate behind you (so you cannot retreat into the boss's room).
The major downside of this area is that enemies will approach from both ends, meaning they naturally flank you. Stealth is pointeless here, so pull out your best weaponry (rifles most likely) and deal with the enemies. I used the small alcove at the North West corner of the rail yard (all the way left as you exit the boss's room) as it gave decent cover and prevented back attacks by spawning enemies. Combined with a sniper rifle, I could easily pick off enemies who strayed onto the tracks. This spot also protects the player from the sniper in the helicopter above.
Once the ground enemies are cleared away, take careful aim and pick off the sniper in the helicopter. Doing so should make the chopper retreat, giving you time to make your exit without being chased by enemy forces. Once all the enemies are gone, the mission will (mercifully) end.