He wasn't sure. The information I know about the source and background of the Ao Ao awaiting arrest comic is very limited. It could be adapted from a novel or an original. If you can provide more information about the manga, I will try my best to answer your questions.
The significance lies in its ability to evoke strong feelings and set the tone. It enhances the overall experience by emphasizing the drama and importance of the story's themes.
Sometimes, it's the audience's interpretation. Different listeners might perceive and construct their own version of who lives, who dies, and who tells the story based on their emotional response and imagination when listening to the instrumental.