Go to Custom Games, Choose 343 Industries: Arena: Attrition
Under Match:
Round Limit: 1
Rounds to Win: 1
Respawn Delay: Instant
Under Health & Damage:
Damage Resistance Ratio: 0%
Team damage resistance: On
Team damage resistance ratio: 10%
Max Shield: 0%
Max Health: 10%
Under Bots:
Team Eagle Bots: 4
Team Cobra Bots: 0 (no enemy bots will get in the way)
Under Attrition:
Team Respawn Count: 1
Respawn Action Time: 1s
and now launch the game
As soon as it starts, use your assault rifle to hit your allies which will die with 1 bullet. On your second teamkill, your allies with turn into orbs and be revivable. Revive 3 different times (can be the same person), and the achievement unlocks. Done in 2 minutes!