1. Noble Six became a Precursor
The Precursors were god-like beings that arrived in the Milky Way billions of years ago and created all sentient life in the galaxy. Furthermore, they assumed many forms throughout their existence, including the Flood. Could Noble Six have become a new form of Precursor when that Elite Zealot skewered him with an energy sword?
2. The Elite that was going to stab Noble Six slipped on a banana peel
The last shot of Noble Six showed him on the ground, surrounded by Elites, and with an Elite Zealot swinging an energy sword down towards him. However, before the energy sword impaled its target, the scene cut to a view of Noble Six’s helmet. It could be possible that the Zealot, just before stabbing Noble Six, slipped on a banana peel at the last moment. This bought Six seconds of precious time, allowing him to slay the rest of the Elites and escape the doomed planet.
3. Noble Six and Jun met up and swapped armor at some point between the missions’ ‘The Pillar of Autumn’ and ‘Lone Wolf’
With Halo: Initiation confirming that Spartan Jun survived the Fall of Reach, and it being implied that some degree of time passed between the last two missions of Halo: Reach, perhaps Noble Six and Jun crossed paths at some point prior to Six’s fate. Maybe, just maybe (and ignoring the considerable amount of evidence absolutely confirming the contrary), Noble Six and Jun swapped their armor; essentially, it was Jun, not Six, who was slain by Elites at the end of the game.
4. The Elite Zealot decided to spare Noble Six and marry him
Look, love is a complicated thing. We have no control over who we love. Because we never actually saw the Elite Zealot kill Six, there is nothing to deny that the Zealot, just as the energy sword drew close, fell in love with Six’s immaculate and non-helmeted face and then decided to marry him, rather than kill him.
5. Armor lock
Armor lock was perhaps the most hated aspect of Reach’s multiplayer, but it could have played a vital role in Noble Six surviving the Fall of Reach. Just before the Elite Zealot could stab him, Noble Six could have gone into armor lock. The armor lock would have shielded him from the energy sword, lasted long enough to make the Elites give up, and then lasted long enough for Six to survive the nearby glassing. Besides, if Six truly was dead, why didn’t we see his body during the epilogue?
6. Halo: The Fall of Reach revenge-retcons Halo: Reach
Reach’s campaign was widely criticized for its outright contradiction of the 2001 novel, Halo: The Fall of Reach. In this scenario, The Fall of Reach, fueled by a lust for vengeance that the likes of which the world has never seen, becomes a writer at 343 Industries and achieves one mission: retconning Halo: Reach so that Noble Six ended up surviving the story.