Go through the glass door and head to the bathroom, which is the first door on your right. Inside, you will find an unsuspecting agent. Eliminate him with a headshot.
After that, exit the bathroom and continue down the corridor. On your right, you will find two more agents. Take them out in quick succession using headshots.
Once you are done, return to the server room and hack the FIB database. This is a mini game where you need to arrange the circuit blocks to create a continuous line between the start and end points. Be careful, as you cannot fail this even once if you want to complete the Elite Challenge. When the start and end points are connected, you will see a green light turn on at the end point. Only confirm the hack after you see the green light.
Once you have hacked the database, the FIB agents will be alerted and additional agents will spawn. Before proceeding to the roof, double back, as two more agents will appear. Eliminate them for easy headshots toward the Elite Challenge. You can see them appear on your minimap.
After eliminating the two agents, head toward the roof. Go up the stairs and, before reaching the double doors, switch to an automatic rifle, as there are many agents beyond them. A useful trick here is to shoot the doors to reveal what is behind them before entering. Use the doorway as cover and peek out slightly to eliminate the agents. Remember to go for headshots, as you need as many headshots as possible.
Once you have cleared most of the agents in the area, run across the room and enter the communications meeting room. This provides good cover against the agents on the roof. From there, keep going forward while eliminating any FIB agents you see before heading through the door to the roof.
Once you are on the roof, quickly land headshots on the FIB agents and enter the Swift helicopter.
Start flying toward the Avi icon on the map, and you will notice that enemy chopper missiles begin firing at you. This is intentional and part of the mission. You will eventually crash on the beach.
Once you land on the beach, start moving immediately. Do not go through the sea arch. Instead, take a left and eliminate the FIB agents you see from that direction.
Going left provides a clear view of all the agents and allows you to eliminate them quickly, rather than waiting for them to approach one by one while taking cover under the sea arch. This is important, as you still need to finish the mission in under 10 minutes to qualify for the Elite Challenge.
Enemy helicopters will also spawn in this area. If you have a Railgun, you can take them out with a single shot. If not, eliminate the pilot and you should be fine.
For enemies positioned farther away, use a sniper rifle and aim for headshots.
Once all enemies are eliminated, use one of their vehicles to drive across the beach and reach the Sea Shark more quickly. Running across the sand on foot will take too long.
After that, drive to Avi as fast as possible to complete the mission. If everything was done correctly, you should complete the mission along with the Elite Challenge.
Once you reach Avi's boat, you will have successfully completed the mission and will be shown the final ending cutscene. We were able to complete this mission solo on Hard mode in 8 minutes and 49 seconds while completing all Elite Challenge requirements.
Once you have completed the finale, you now unlock a secret Michael mission called "Home Sweet Home." Here is how to play it.