Picture this:

Because your guns get reset every time you die, you've gotten used to saving in between every single mission and resetting to that point whenever you die. You've been stuck on this same mission for about half an hour by this point, and you are resetting to attempt it once more. However, this entire playthrough the text on the menu has faded in extremely slowly. You mistakenly click "Erase saved game" instead of "Load Save Game". You are 3 missions from the end of the game. You are me.