Cosmic Crisis [Sabotage Mission Failed]

So on my first game someone sabotage the mission and I wanted the achievement so bad. So I tried on my next game. Figured, its hard on Normal mode since monsters spawns are more calm and if I wasn't the healer (No healer = They are dead) Plus with Roadhog and Torb on their team its gonna be hard for me Lol. So yeah, learned that the heard way and I attempted next on Expert or Legendary Difficulty.