''Aggressive Negotiations'' Achievement
Defeat 3 enemies at the same time with an explosionYou can earn this at any time during the story or in Free Play and will likely unlock without even trying.
The most common method for this is to shoot or Force Throw a red (or yellow) explosive canister around/into a group of enemies. This can be done on a number of levels, including:
1 - Episode IV, Level 2, ‘Hunk of Junk’ - While defending Chewbacca, Stormtroopers spawn in the alcoves around the hanger and take cover. Placed at strategic locations are yellow explosive canisters. When they appear, shoot the canister.
2 - Episode VI, Level 1, ‘A Plan to Save Han’ - When you first start playing as Luke, there are a few Gamorrean Guards standing around a few explosive canisters. Since the guards aren’t reacting to Luke, destroy a canister at your convenience.
Another, less-effective, method is to throw enough grenades into a group of enemies in hope that one explosion defeats at least three of them. The only drawback to this is that grenades only deplete an enemies’ health about a third, so keeping three together long enough to defeat them all is random and unpredictable.
Despite what the description says, it does not need to be three enemies; it can be a combination of any three characters. For example, if you are standing next to an explosive canister with your teammate and an enemy or another NPC is close by, if you shoot the barrel and defeats you and the two other characters when it explodes, this will count for the achievement.