Season of Migration to the North Lesson Plan

Why does the narrator finally decide to enter Mustafa's secret room? What happens in the secret room that makes the narrator thinks he begins from where Mustafa had left off? What is his response to this conclusion?

After the narrator fights with Mahjoub and attempts to strangle his old friend, he blames the act of violence on the influence of Mustafa. He is full of hatred and wants to seek revenge, in much the same manner that Mustafa wanted to take out his anger on his lovers in England. The narrator decides to go to Mustafa's secret room to confront Mustafa's ghost and exorcise his influence. When he lights a match in the room, he is startled to find Mustafa...