This is when you complete a mission without dying right? well, if so that’s like impossible for me (im playing on heroic). I’m trying to get a flawless on all missions but I just can’t some random suicide grunt or bullet-sponge sword elite keeps murdering me. and that part on the misssion infinity when you have to defend the area from hordes of prometheans while cortana opens the dorr is almost impossible on heroic without dying. Any tips?