Kill 1 unfortunate Helghast soldier with 3 rockets from the BLR-06 Hadra

Load up the ninth chapter, Hidden Pasts, and as soon as you enter the first tunnel, go through the door on your right, and climb up the ladder to find the BLR-06 Hadra. It is a Rocket Launcher that houses three rocket tubes, and comes with two fire modes. The primary fire allows you to fire one rocket at a time, whereas with the secondary fire, you can unload all three rockets at once. You have to use a fully loaded Hadra's secondary fire on a poor soul to unlock this trophy. After you acquire the said Rocket Launcher, get up close (but not too close) with any Helghast soldier. If you are too far away, the rockets will disperse and likely miss the target in the process. After all three rockets hit the enemy at once, the trophy will unlock