- last post: 01.01.0001 12:00 AM PDT
i shall take pity and answer..
sgt had suffered some kind of nerve damage from handeling too many plasma gernades. as a result of that he cannot be completly infected by the flood. so while he still has the flood virus in him they cannot complete the infection becase of the damaged nerves.
the legendary ending where it shows him hugging an elite while Halo explodes is just a funny little extra. it wasn't intended to be the actual ending. if you read the books it explains that he got off the planet. and the whole flood infection thing.