These are the seventh, eighth, and ninth missions of the game.
On Science Center Exterior, you will have to snipe 6 people before you can do anything else. After you snipe them, you have to move down an alleyway, remember to be stealthy so the enemies don’t bring in reinforcements.
On Science Center Interior, you have to move through the Science Center and kill all enemies. Remember to use a lot of cover or you will get killed.
On Airport, you have to upload an antivirus from two locations to your phone and then to another computer. After this you have to stop the bomb maker from blowing up an airplane. Remember to be very stealthy at the beginning of this mission and use a lot of cover throughout the whole mission.