I'm positive I know where this is going...
I guessed it when I watched this the first time but i'm sure of it now. She was obviously in a car accident and now she's in a coma. Note the way cars are stuck inbetween things, the way roads are a used as a theme. The splintered glass in the background at the very begining is a broken winshield. You hear sirens at the end like you would at the scene of a car crash. What really gives it away though is the phone call. If you listen to it and consider that the first voice is obviously her boyfriend or brother and the second is the doctor then it makes alot more sense then the suicide theory. Its also obvious the accident was caused by some rabbit in the road that she swerved to miss. Consider that when he walks up he says that she "gave him quite a scare" though he's not talking about at that time because he introduces her and adresses her rather nochalantly, he's talking about before when she almost hit him in her car.
It don't say all this to be a dick and ruin the series for those that read this review. I say this so that the author might read it and decide to change the story.