Forum:Can't Keep Everyone Alive on last Mission

On the last mission when you kill the Human Reaper, (Mass Effect 2) The game goes to a cut scene where your squad gets out. Every time I replay the last mission, during the cut scene there is a part that show one of my team members dead. I have replayed the mission 3 times with diffrent people coming with me, but someone always dies, so I couldn't get the ''No one left behind" Achievement.