The tail section group was obviously in some sort of man-made structure (or at least man-altered cavern) so was this another station or a connection to the swan station? If a connection, why did they not find the connecting passage since it appeared they had been there since the crash.

__________________
Things fall apart, the center cannot hold;
Mere anarchy is loosed upon the world,
The blood-dimmed tide is loosed, and everywhere
The ceremony of innocence is drowned;

--Lines 2-6, "The Second Coming" by Wm. Butler Yeats