I still don't see what you did wrong, InACorner. Telling someone they're disturbing others and would they please be quiet isn't wrong, nor is closing the door, since she was still loud/disturbing others. You weren't "mean" or hurtful, just truthful and trying to be helpful. You went to her and asked her if you could help in any way! Her behavior is out of line, just because she is sick, she cannot be allowed to hurt others which her noise clearly does. I think you were very caring and professional.