This 
is a picture of Terri before her heart attack, a photo which you’ve seen a hundred times before
And 
this is a photo of Terri after her heart attack, which left her brain without oxygen for fifteen minutes and reduced her to a Persistent Vegetative State.
Notice the unmistakable vegetable qualities. How can anyone think that the person in this photo is human? Or, if she is human, how can anyone think that such a girl as this wouldn’t want to die? See how miserable she looks? How grotesque? Obviously she wants to die now.
If the girl in that first photo could have seen this second photo, I’m sure she would have said “Michael, if I ever get into that condition, promise me you’ll let me lie unattended until I die of thirst.”
For the true state of the medical question (is she a vegetable?), see this article.