I got this Achievement Playing Wesker Mode. Also had infinite Ammo Unlocked as well. Pretty Simple Achievement for anyone to get. Just don't Heal Yourself!! lol. U can use Wesker's Death Star to make it more easier. I also used the Magnum Revolver as well that u find on the Train. Once u beat the Game. The Achievement Will Unlock. Perfect Runs for Not Saving, or Using Frist Aid Spray. Here is a Full Walkthrough Video of me Unlocking it in Wesker Mode :)