3 0 0Actions Report Solution I found a place that might be a little easier. Still on the first mission on Recruit, you'll come to a part where a smoke grenade is thrown and you're asked to throw a threat grenade. Do so, then quickly run up, and throw a smart grenade and back up. 6 guys will be coming down the stairs when the smoke grenade is thrown, and they'll be fairly close to each other, making for a real easy place to get this trophy.
2 0 0Actions Report Solution I did this during the first mission on Recruit difficulty.You will come to a street with lots of bars and restaurants. At the crossroads there is a bar on the left front corner with pink and white lettering above the door. Kill your way through the first floor (trying not to kill enemies in the windows upstairs) then run up the stairs. There will be a group of enemies across the room. I tossed two Smart grenades to be safe and the Trophy popped a few seconds later.
0 0 0Actions Report Solution This trophy/achievement can be achieved in Mission 3: Fission. When you go forward you will see some groups of multiple enemies. Use a threat tactical grenade to see how many enemies are standing close together.