Mission 05: Open Your World
Objective: Meet Badboy17
Head inside the subway entrance next to Aiden to enter a cut scene and meet Badboy17. After the brief meeting, you will have access to all skills (provided you have the skill points, meaning you can start customizing Aiden's abilities however you like). Jump into a nearby car and head for the new objective marker once you are done.
Objective: Reach the ctos executive offices
The executive offices can be reached via the underground garage / parking lot beneath, so take cover nearby and take control of the camera over the entrance door. Head to the back of the room (around the corner to the left),following the camera trail to find a locked door and a control panel on a nearby wall (follow the white wire trail connecting them to locate it). Unlock the door using the control panel.
Now that the door is open, Aiden needs to reach it. Make good use of the guards distract opportunities to quickly move into the garage and then distract the guards watching the door to slip through (you can engage in a firefight or pick them off with a silenced pistol, but due to the clustered nature of the security forces this tends to end badly). Keep in mind that as well as distracting them using your phone, you can use lure items as well. Inside the door are a couple of rooms with an item or two inside, grab them if you want before moving on.
Objective: Locate a guard with the access code
The guard you want to scan normally walks around the center of the lower floor, so hack into the cameras and look around the lower floor until you find him. Once you do, you will want to stay in stealth if you can, as it can be difficult so survive in combat here unless you are a damn good shot.
Hop into the camera at the end of the room and you should be able to connect to a camera on the second floor above. A patrolling guard up here has a hidden camera on his vest and patrols into the room containing the panel you need to hack, so take a ride inside and hack the panel. Once you are in, you will need to contend with the simple pipe dream mini game twice (watch the mission video if you are having problems).
After the successful hack, you will be looking down into an office. Hack the computer on the desk (if you used combat, a guard invasion will be triggered here) and retrieve the data. If you didn't trip any alarms or alert the guards, you should be able to quickly exit the building, drive off and use your jam coms items or driving skills to evade the police scan and complete the mission.
If you did alert the guards, the guards will arrive in force. Take a good cover position (I used the room Aiden was standing in when he hacked into the office) and pick off the bumbling guards one by one. One or two even have explosives on them so have some fun (it's nice not stealthing once in a while). After the guards are wiped out, try and leave the building to find a police scan in progress.
Use the jam coms provided to gain some time and grab some wheels outside the building (to exit, head down to the lower floor and back out of the garage. Plenty of vehicles should be available so hop in one and hightail it out of there. After escaping the scan / police chase, the mission will end.