This movie is difficult to categorize. It it unique in many ways. It is a murder mystery (or seems like there was a murder of a patient during surgery, or maybe 2 murders); a stalker movie, but by a woman (or she appears to be a stalker), you see the way it is going.
This movie is incredibly claustrophobic. People have more than one purpose (role). Everything and everyone intersects in different ways (a hard concept to explain, but remember the woman stalker, or is she).
Here is a surgeon. He can't practice medicine anymore because he has panic attacks, while reliving a surgery gone bad. His wife is a medical malpractice attorney who picks up a case from a woman who was her husband's nurse.
It starts out quiet, then it takes you on a roller coaster ride. By the second half, the tension level is at a fever pitch. By the last half hour, I was wishing I had recorded it so I could fast-forward to the end. When it was over, I wish I had not seen it: I don't care for movies that have a high tension level. But ... if you like tension building up and up (with confusion piling up, layer upon layer), this is your movie.