What scary movie is it?

It was a scary movie. I watched it on On Demand on comcast. It was about a bunch of college students that were training to be doctors. And they have to work on cadavers (donated dead bodies) and their cadavers spirit starts killing students. And the main character and another student figure something out about the cadaver/spirit and they go into the operating room and ther is a big metal and glass box filled with the cadavers in liquid and they have to get their cadaver out that is killing everyone. Its been driving me nuts haha i cnt find it anywhere