Mary Vernieu is a bit weak here

I watched The Killer Inside Me (2010) and Mary Vernieu was one of the parts I kept noticing. I do not hate it, but it did not pull me into the story. Some emotions are too simple, and I cannot believe the character enough. The role needs more detail, but the performance stays on the surface. Many moments pass very fast, and I do not remember much after them. Maybe other people will like it more, but this is my feeling.