Mission 06: Thanks For The Tip
Objective: Reach the mystery caller's signal source
After regaining control in the alley, head deeper in to the open area beyond. The objective marker will be pointing to an access panel, but it needs to be unlocked first. Meaning that both inputs need to be found and activated.
Objective: Find and activate the ctos boxes
For the first, head to the east edge of the circle to find a lift that Aiden can ride. At the top, you should be able to hack a camera directly next to the lift where Aiden is standing. While in the camera, make the lift descend again to reveal the first box to unlock on the opposite wall.
The second box is equally simple to reach. Head back to the middle of the circle on the map and look for a different lift, sitting next to some scaffolding. Use it to reach the top of the scaffolding and look for a camera overhead. From here, you should see the box on the wall across the gap to your left. Unlock it to activate the access panel.
Objective: Access the building network to reach the signal source
Head for the now working panel and hack in. Pipe dream again people (watch the mission video if you need help). Once Aiden is in, you will be looking through a camera in a very messy room.
Objective: Investigate the apartment
After a few seconds, a new objective will flash up.
Objective: Hack the phone
Once you hack the phone, you will have a nice little chat ending with a warning. Exit the network to find things have taken a turn for the worse.
Objective: Kill all fixers or escape
Grab cover (and raise the nearby protector panels if they aren't already) when you regain control. A large group of fixers will be arriving from both alleys, so you are in for a firefight (escaping in a car is far more difficult as you will be shot to pieces trying to reach one and then overwhelmed by the fixer cars most likely). Looks like fighting is the best option. The enemies are all just grunts at this point of the game, so a single headshot should take each one out easily, the only problem is having long enough to aim.
Use a pistol (pinpoint accuracy and quick to reload) to ping enemies in the head, prioritizing distance and weapon type (eg: close enemies with a shotgun should be taken out immediately). As long as you use cover well and watch the mini map for flanking attempts, these enemies shouldn't pose much threat and should be crushed pretty quickly. The one good thing about this firefight? The cops won't be called. Once the area is clear, a new objective will flash up.
Objective: Follow the traced call to Damien
Hop in a car and drive to the park to reunite with your old partner and after a cut scene, the mission will end.