March 21, 2012In James Cameron's ALIENS we are introduced to the idea that a Queen Alien laid eggs, humans are harvested by adult aliens for impregnation by face huggers. The original idea from the first ALIEN film was that when a host was cocooned, they go through a kind cellular metamorphosis and transform into the next egg containing a new face hugger.
If we assume (yes we all know what that breaks down to), the only 'victim' of a chest burst is the Space Jockey in his chair (telescope?) and if the idea of the mutation/transformation idea is correct, then all his crew became the eggs at the bottom of the ship and the alien that burst from his chest was the creature that cocooned the others. What exactly happened to that creature is anyone's guess.
Once on board the Nostromo, we have Kane who is the chest burst victim and later (in the director's cut) Ripley finds Dallas cocooned. He is already going through that metamorphosis before she flames him and the nest.
Just a theory based on what information is available from the extras on the ALIEN Anthology Blu-ray Disc [6 disc] set.