Things You'll Need
Instructions
Listen to Diaz as he sees you off. You will begin the final mission of the game in a helicopter. Fly the helicopter to Mendez's penthouse.
Attack Mendez's guards with the helicopter's weaponry by pressing the "Circle" button. The guards are numerous, but they should not offer much of a fight. You will be shot down by a rocket launcher.
Take the RPGs laying in front of the door. Swap to a nonexplosive weapon and enter the room ahead. The hallway goes left and right, with enemies present on both sides. Sneak carefully around and you will be able to take your time disabling them.
Follow the marker and descend the staircase. There will be a few enemies in the room, so dispatch them quickly. Use the desks and file cabinet as cover.
Ascend to the higher floor. A helicopter will appear outside the window. Hide behind file cabinets to avoid its fire. Two enemies will also attack from the other side of the hallway. Alternate between killing the respawning enemies and using the RPG to fire at the helicopter between its rounds.
Approach the roof. After the in-game cut scene, turn around and climb up the building you just exited. Mendez and Martinez will be unable to significantly damage you, and you can easily pick off both. The main story is now complete, and you can explore the many side jobs and optional missions available.