I thought this was a bad one but i just equip the last word once I'm sure we're going to win so it counts and if i happen to get a few kills with it while i'm hiding all the better and that way if i die i still get some the original boost. I went from 7 percent to 60 something in a few days as i wasn't putting much effort into it since i was doing other stuff. Just use my method and don't take any risks you don't need to, it'll take a while but it's safer than guns blazing.