Kill 4 enemies with a single smart grenade.

Mission 1: Induction

About halfway through this mission, you will reach a subway station and pass through a train. Once you go through the train, you will be told to throw a threat grenade. Throw one at the bottom of the stairs and it'll reveal about 6-7 enemies. Now simply throw a smart grenade ( [ Register or Signin to view external links. ] on PS4, [ Register or Signin to view external links. ] on PS3) at the group and it will kill 4 of them as the blast radius is fairly decent. If you mess up though and the trophy doesn't unlock, simply restart the checkpoint. For a visual walkthrough, refer to the video below: