This cheevo is very simple to get.
From the main menu select the FIRETEAM ENGAGEMENTS option and select LAST STAND mode on the top bar.
Now choose either one of the maps available and start the mission.
Head to area 1 and take out the 1st wave of enemies and as soon as you finish wave one head back to the extraction point. A helicopter will come to you automatically. when it arrives jump on board to end the mission.
To get this cheevo, it does not matter how many points you get as long as 1 of your team gets back to the chopper i.e you.
Of course you can play and kill enemies as long as you like but you will get the chhevo only when you board the extraction chopper and end the mission.