Level 40 Using the First Mission: A Guardian Rises

UPDATE: Want to know the finer details behind this? Check out the Reddit post: Yep. Level 40 using only the very first mission, which is called, “A Guardian Rises“. That's the mission where Ghost wakes you up, and tells you that in order to live, you need to get through the Wall and collect your ship. Except I never collect the ship. I go to Orbit (or in this case 'leave game') and then load back in, only to kill all the enemies again. So long as Rahn lives, the mission never ends.