It's been two years, she could have dyed her hair or something.
Also, I have a weird feeling that players killed in the game do not die.
I have a feeling it was a hoax to fully test the nerve gear, however there is no way to logout anyways and no real way to communicate with the outside world. Also the nerve gear can cook their brain if forced off so that part is possible, but being killed in-game is likely not causing death. I'm suspecting it's the drama to keep people constantly playing, if it was otherwise people would be killing each other to leave the game.