This is achieved on Mission 3 (Fort). At the end of the level you will be faced with a locked door, when Doyle starts hacking the door you will need to survive for about 90 seconds until the door is hacked open. Two boats will spawn and start shooting rockets at your area which kill you if you do not retaliate or hide.

The safest way to survive is to make your way to the left of the door, down the stairs and hide in the small tunnel until you're notified by Doyle that the door is open. Three mercenaries will be dropped off at some point and may or may not make their way own to you, so be cautious and ready to kill them. Achievement will unlock once the door opens.

Alternatively, you can choose to take the boat enemies out if you have a sniper rifle and then the chopper enemies with your assault rifle. See video for further help: