Students have a difficult time limiting their analysis to one portion/segment of a novel. This exercise allows for students to examine a selected passage as a casement--a window that is attached to its frame by one or more hinges. Teachers just have to remind their students that they can only see or consider what is visible through the window.
Consequently, this activity requires that students list the events in the casement and then explain its significance/relationship to the theme of the passage. They are forced to only consider the events within the SCOPE of the designated text for their analysis.