JohnnyFootball
GerAlt-Right. Ciriously.
According to the Alien Audio Commentary (or the making of featurette, I forget which) the Alien has the ability to turn people into eggs. During the deleted Dallas scene at the end of the movie, you can see Bret is already in the process of turning into one.
Love that page. Excellent interview with Walter Hill.
My view is that the alien in Alien is a drone and is not a queen or hasn't grown into a queen and therefore the morphing lifecycle is more or less a quick mean to make an egg.
We could also take it a step further and say that the morphing is needed to produce a facehugger that can produce a queen. There are lots of ways to connect the two lifecycles in ways that are plausible.
James Cameron though has stated that he chooses to ignore that scene since he felt it would hamstring his film and that it is a deleted scene that the audience would never see. This was 1986 and deleted scenes were rarely shown publicly and most people who had seen Alien would have no idea of it's existence. IIRC, Ridley Scott also does not consider that scene canon since it is not in his preferred cut.
Back to Alien Isolation:
It makes most sense to me
that the queen is present in the reactor, but CA chooses not show it, especially since we don't see any humans undergoing the same things as brett is.