Dramatic elements are resources used by writers in order to convey a dramatic effect on part of the performer and then to have an action that is important in a number of ways , obviously depending on what the writer wants to show.In this case the element"<em>...after the music has ceased..."</em> gives an idea of sequencing , action after action plus the contrast between this character being alone and then in the company of Algernon.
It is important to understand that there is more than one way to look at a problem. Sometimes changing the way a problem is represented, in this case, CAN lead to overcoming problem-solving issues. I know this is basically repeating the question, but it definitely true for me as a current psychology student. Hope that helps :)