Lack of speech, lack of music at first, when Norman Bates walks in the camera focuses on the shadow behind the shower curtain and the music starts when Bates is revealed behind the curtain with a knife. The music starts (same sound as a curtain reel moving that screechy sound), when Marion Crane starts screaming it zooms in on her face. The camera flicks between the two characters showing that there is a struggle. Camera doesn't show Bates' face as it's supposed to be a surprise as to who is the murderer.
When Bates finally starts to stab Crane it flicks between him lunging the knife and her reaction and then including close ups of her body to show where she is being stabbed. The camera also moves between the two characters more to show how confusing this scene is. She was showering and the next thing she is being attacked by a killer, shows that she has no chance to defend herself. Camera then flicks to the bottom of the bath tub where her blood is flowing to show that she has been stabbed. You see the mystery character leave immediately (which is again strange for someone who has Just killed someone).
Then there is the famous close up of Marion's hand as it starts to fall and she starts to exhale loudly to highlight the fact that she is badly hurt and the music has went from a very high pitch toa high low pitch to show that this is bad. Her hand Is then focused on grabbing the shower curtain to try to get out , but it rips off- symbolism that she is gone, that she has no hope. Shower's still going (don't know why) and as soon as she collapses on the floor, the music has stopped - again showing that there's no life left In her.
The camera hen pans away from her feet In the tub, with the blood running through the water with the only sound being the shower that Is still on. With the camera closing up on the plughole and fading Into Marlon's eye as they zoom out she's lying on the ground motionless with what seems like tears on her face (from the shower). Camera looks around the room as If In first person and then looks out the window up at Bates' house where he Is questioning why his mother done It. Bates runs down frantically and the camera stays on him as he cleans up the mess. Showing Marlon's motionless hand.