Creature over Shaw's head in med pod came out of sj head?

Looks like the creature over Shaw's head on the med pod scene, must have came out of the exploding head of the sj...I think that is what we are seeing after the sj head explosion in the new international trailer, going directly up and strategically moves out of frame almost in no time... Which makes me wonder.... Why this thing was growing in the sjs head? And why was the sj deheaded anyway? Did his people do that to try to terminate the growing parasite? And did it come back to life again? Is that a capable survivor, able possibly to maintain life even if the host is dead, until it can re-host somebely else? Sjs were used by the Gods as we are in this movie? Did they love us and made the trip to Earth to warn us? Were they under attack by the Gods when run in the hologram? Did they want to come back to Earth to defend us from the Gods not unleashing their punishement on our planet as they did on theirs ? And have they failed into one of their experiments that performed for themselves (the sjs) stealing Gods's technology to find a way to fight back for the reasons they were used as live stock by the Gods? Questions...