By watching this scene insted of reading it silently, the viewers cannot infer what the characters are feeling at the time of the action.
The author of the play adds very important information about what the character of Madeline feels upon entering Fred Jordan's cell. He explains that "she is in that cell; she is all the people who are in those cells."
This information could not be taken from context only by watching the play, it would be necessary to read it to understand it.
