yeh we r doing witness for close study of text. im not sure what ur essay qstn is, but witness is such an easy text to discuss. being a movie you really have to talk about the filming, camera, music and sounds and stuff. watching the movie and taking down notes like example, when Sam witnesses the murder we can see thru the POV shot, you should explain the effect this particular camera angle has on the audience (you). we fell scared and sympathetic for Sam and know that witnessing this is going to have consequences for him. but yeh most importantly discuss how you are bought into the film thru the techniques.