Gang Lu stands up and leaves the room abruptly; goes down one floor to see if the department chairman, Dwight, is sitting in his office. He is. The door is open. Gang Lu turns, walks back up the stairs, and enters the seminar room again. Chris Goertz is sitting near the door and takes the first bullet in the back of the head.
This transition to the story was a bit sudden and confusing, why did Gang Lu suddenly go on a killing spree?