You believe wrong - the autopsy did not prove she was in "a vegetative state." The M.E. reported that pvs is a clinical observation - one he couldn't observe on a dead person. Terri was dehydrated to death - that makes her autopsy rather subjective as to the shrinkage the dehydration caused to her brain. That's nice that you would not want to be in her condition (you probably mean before her barbaric murder by dehydration); but, that hasn't squiddly to do with what she wanted.
I guess you are in the medical profession.