I'm not sure if I'm explaining myself clearly.

He delivers his lines from the same place but with the door shut not open (remember the door was left open to let in the droid) with the door shut the scene is more claustrophobic.

The scream is then silenced by the scene change, the guard walking down the silent corridor (with the door shut).

This maintains the flow of the original version while adding the nasty idea that in each of those cells is another person being tortured.

I would add a slight delay between the beginning of Mr Vader's close up and the scream.

Remember Leia isn't screaming at Vader but because of something he is doing with her mind which may take a fraction of a second to switch on.