This achievement is story-related and cannot be missed.
*** Spoiler - click to reveal ***During the mission A Trail of Hope, you'll get to a kett exaltation facility on Voeld (may also be on Havarl, but can't confirm that myself). Fight your way through the facility and at the end you'll have a boss battle against the Cardinal. Defeat him by shooting the rotating orb until it's dead and then unload on him with everything you got before the shield gets back up. Avoid the orange energy spheres casted by him or you'll instantly die!
Once the Cardinal's 'dead', you have to make the choice to either rescue the angara prisoners or to destroy the facility. If you're quick, you can also kill the Cardinal. After making your choice and extracting, the achievement unlocks.