After you enter through the gate, there are two soldiers in each of the three rooms on the left. The farthest room has armor. Shoot out one of the windows on the right and jump-crouch through.
Clear out this dock area (including the sniper tower above) before entering through this door.
You'll find heavy opposition inside. That room ahead has a single soldier but provides good shelter once he's dispatched. Note the medium medkit on the left. Armor is behind some crates on the right. Climb the stairs.
Search the area for supplies before passing through the door near the top of the stairs. Climb this ladder.
Soldiers await atop these air vents. Clear them out.
There's also a sniper tower as well.
Step down to the roof below and drop through the indicated air vent.
Activate your night vision and crawl through the vent.
Descend this ladder.
Fight your way through this corridor. Activate the green control panel to pass through the door ahead.
Fight your way down this corridor and hang a right at the end.
Continue through this door.
Collect supplies in this room, including a large medkit, armor and ammo. Climb the ladder.
Prepare for a firefight before proceeding through the door on the right.
Defeat two soldiers behind these crates.
Your sniper rifle makes short work of these two -- the soldier in the tower is lobbing grenades your way.
Proceed further down the dock, fighting your way to that corner office.
Activate the main gate switch and your mission goals are updated: open additional gas source (GV1 and GV2).
Climb these stairs.
Defeat these guards and search this room and the room below for supplies before descending the stairs ahead.
Continue through the door on the right.
Defeat these two guards, then descend the ladder to the immediate right.
Grab all the supplies you need.
Backtrack past the main gate control room to the indicated elevator.
Defeat the guards and pass through the door directly ahead.
This large firefight ensues. Hold back at this corner and let them come to you. Advance to the crates ahead to take out the stragglers.
Shoot the wooden board blocking this door.
Continue through either of these wooden doors.
Fight your way to identical wooden doors across the room.
Activate the green panel to proceed through this door, and another just like it ahead.
You've circled back to this position, but because you've shot this board, you can now proceed through the indicated door.
Continue through this door to the left.
Pass through the door at the top of this long ladder.
Ready for a fight before descending this ladder.
As you fight your way to the bottom level, Kabir instructs you to turn two valves.
Turn both valves and your objectives are updated: increase the flame controls in alphabetical order.
Ready for a fight before descending this ladder behind you.
Defeat the guards before turning these valves in alphabetical order. Kabir instructs you to increase the output of the generators and return to the gate. Enter the generator room seen here on the right.
Activate the panel on both generators to complete the goal.
Backtrack up this ladder.
Go through this door between the valves.
Exit out this door to the dock outside.
Walk farther onto the dock to initiate a cutscene.
Ambush! Tommy, the new head of the Family, is determined to kill you.
You don't have to defeat the Family here. In fact, I never fired a shot. Just make your way to the main gate control room.
Activate the main gate control.
Kabir thanks you in the ending cutscene, then the submarine is loaded and it sets sail.