Once Colonel Everett Young finds the armory, in the part that looks like the SGC -- once he gets a sidearm -- he starts exploring the area around him.
He avoids the transporters, keeps track of where he is, and finds that he can actually passably navigate, if he assumes that the Destiny, the SGC and Atlantis have all somehow been jumbled together. There's no explanation forthcoming; the computer systems all seem normal, and the Ancient language is still, as ever, completely incomprehensible.
Best case scenario, he wakes up from this and finds that it was some kind of alien illusion. Slightly worse case scenario, he finds Rush, or someone else from the Destiny.
Worst case scenario, he doesn't.
Whichever it is, he'll find out soon enough.
Original post is
here.