Did Chell really leave Aperture Science?

[Harry]

If you can remember, the exit of Aperture Science is a parking lot in Portal. But when you leave Aperture in Portal 2, you can see you leave an innocent looking shed, (then GLaDOS give you the companion cube that you burned in Portal!). If you also remember you get tossed out of Aperture in Portal after "killing" GLaDOS, and GLaDOS is in the same spot that you get tossed out of, so if the elevator is where the parking lot is, where is the parking lot? Maybe it is a fake room that GLaDOS didn't know about, or it might be all the time they spent after Portal. But where is the Combine? Did Gordon Freeman finish them in the never coming Half-Life 3?

[Λvery]

Well, it HAS been an unknown amount of time between the two games. So, it might've been long enough that the concrete crumbled away and someone came along to plant the wheat.

As for the shed, idk really. Maybe Wheatley moved her chamber up and somewhere else and she just moved it back down and not back to it's original position.