How suspense is developed in the murder scene of "Wtiness" By Peter Weir

Murder Scene Samuel and his widowed mother Rachel are at a train station trying to get a train to Baltimore to see Rachel's sister. At the ticket sellers booth they are told the train is going to be delayed three hours and are told to move away and sit down. When they are waiting for the train Samuel asks if he can go to the toilet, so he does. Before they left, Daniel, Rachel's would …

…however Samuel in an extreme close up looks through the crack and sees the murder the camera then cuts back and forth between the actual murder and Samuels eye this highlights the notion of him being an eye witness. The music in this scene mimics the fast heartbeat of Samuel, this is so that we as the audience can not only see and hear him but we can also feel the emotions he is experiencing.