ATTENTION: I KNOW HOW/WHY YOURE STILL CHELLE IN PORTAL 2.
Before I figured this out I wondered How u could be Chelle in Portal 2 also. I had noticed before that the very first thing Glados ever says in Portal is,"Hello, and again, welcome to the Aperture Science Computer Aided Enrichment Center". SHE SAYS AGAIN. In the last level of Portal 1, while your fighting Glados, she says,"-And dont worry. I have your brain scans on record in case anything bad would happen to u. Which its just about to" Inferring that even if Glados did kill Chelle, it wouldn't matter cause she could clone her and just have her tested again. So in 200 years, when the lab got running again, the facility simply clones her again, and tries to have her tested but because the lab is old, run down, but trying to be re-built, Chelle is put in completely different circumstances.
Ive been wanting to share my theory with others so tell me what you guys think.