Wasteland 2: Director's Cut (EP)

Cannot be done at Rookie difficulty as it removes friendly fire. Take off all armour and group everyone minus 1 non-NPC party member together then fire a rocket or 3 at your crew in combat, thus killing everyone except the shooter. As long as combat ends and you are left with your shooter and no one else including bad guys, both this trophy and Oops will pop. It's possible this won't pop during a Wasteland encounter so if it's not popping, then try it on NPCs or a regular non-random encounter.