For the similarly named mission in Syphon Filter: Logan's Shadow, see Missing Friends.
Addison Hargrove: "Gabriel Logan. What a surprise."
Gabe Logan: "Hello Addison."
Addison Hargrove: "Still working for the spook patrol?"
Gabe Logan: "Er...Just here on vacation. Heard you screaming, thought I'd come up and say hello."
Addison Hargrove: "Same old Gabe. Let me guess... You give me protective custody, in exchange for my files."
Gabe Logan: "Something like that."
Addison Hargrove: "What makes you any different from them?"
Gabe Logan: "For starters, he's dead."
Addison Hargrove: "Good point. Nice shot... You haven't lost your touch."
Gabe Logan: "Not much time. We gotta move."
Addison Hargrove: "Hope you're still good with a gun."
The first part of the mission is best done using stealth. Go to the very edge of cover, and lean out to snipe the first enemy. Unsnap from this wall and slowly advance to the second guy. Stand a good distance back so the third cannot see you, and shoot his head as well. Climb up to the rooftop, and silently drop down to surprise the third man (on a turret). Use your knife on him for some variety.
Grab his Uzi and head forward, watching out for a fourth troop. Use your pistol to sift his brains, and grab any ammunition from his corpse. Go into the room he came out from to trigger a cutscene.
You must now rescue Addison, who's being interrogated. First, switch to the MB-150's electric darts, and tase the rooftop patrol. Equip your pistol once again and turn on EDSU goggles. Notice the yellow can close to the trolley? Well, snipe it. It will detonate, causing the cart to charge forward and destroy a door, killing a soldier in the process.
Climb onto the rooftop, and wait for Black Viper to turn his back before you use your knife. Open the doors and go to Addison.
Hargrove is somewhat hard to escort without killing. She also likes to complain... That being said, grab the Uzi bullets and then start sniping the enemies on the ground. You will not need stealth anymore so swap your pistol for the Jerico. Head back into the area you began in and a wave of revolutionary infantry members will flood in. Go to the turret and use short bursts (remember to aim high) to kill them. Watch out for snipers and try not to hurt Addison. After a literal killing spree, the spawns will stop and Addison will enter a room. Do so and move the cabinet.
Head into the vent and a Red Section soldier will spawn in the next room. Silently drop down and welcome his throat to your combat blade. A few snipers will assault you from the adjacent rooftops, so switch them off. Drop down into this area, which you were previously traversing, and climb onto the roof to get the Dragunov sniper rifle. Get back down and provide Hargrove with cover. Try not to get hit or get her hurt, again. Once you have massacred the entire area of enemies, the mission will end.
- From the starting point, climb the onto the roof of the building immediately to your left. Grab the overhead pipe directly before you'd climb up to the next roof layer. Shimmy right along this pipe and land on a balcony. Go around and shoot the lock off of a vent cover, then climb through. At the end of the vent is an guard you can easily kill with stealth. Once he's dead, check his body.
- Shoot the explosive tank right at the starting point; use the fire extinguisher and enter the room. Push the file cabinet and crawl through the vent. When you come out into the room, there's a safe. The code is 6-9-4. If Addison is with you, there will be a guard in the room who calls out the code over the radio if you wait.
- Go find this evidence after you've killed "Black Viper" but before entering the room where his body is (where Addison is tied to the chair and calling for help). Go all the way down the new "street". At the very end (somewhat hidden) is a stack of crates: climb them and examine the body.