That was one of my favorite parts of the game, and the song is lovely.
Is there any information about the "I'm different" turret? When you meet it again and pick it up before it is be destroyed, it goes on about Caroline and what is below (the old testing facility). I wonder if it was a previous employee used as a test subject...
I think...
...it might be that the turret uses some of Glados' AI. They share the same voice, after all, and Glados' AI is part Caroline. Notice that the turret also says "get mad" and "make lemonade", both Cave Johnson-isms. It think it also made a moon reference, I don't remember exactly at the moment. Either way, lots of foreshadowing for people who have played the game before and are now making a second run through the game or achievement hunting.
Yeah I was thinking the same thing almost - GLaDOS is Carline. To some degree anyway. I remember in one of Cave's recordings that he wanted Caroline's personality to be put on a disk and used as the A.I. if his couldn't. With Cave getting sick and dying is why I think GLaDOS is Caroline.