it's an interesting thing to note that the name of the piece of music that is playing, i believe, when she is describing the death and murder of theophill
it uses the word "atonality", meaning a song or piece of music without structure or rhythm, in many cases this means without a key or mode.
they could have easily used a different word like insanity to describe the scene, but instead they chose a word related to music. isolde was probably hearing the music in that moment that would fit under the idea of atonality
she is "hearing" this music that does not have true structure, very different from the music she has sung for all her life, which is portrayed in how she acted in the scene with theophil. the "hearing" of music is just a way for her to express her emotions and feelings in a way that she can understand in her broken mind. it's not really her thoughts or actions, it's just the music she hears, the music she is to preform, because before all else she is a opera singer
isolde was molded and groomed into this perfect little caged bird that's purpose it to entertain. its all she knows. all she can do is sing the songs she told to, so who's conducting the songs? who's telling her to sing? it could be the ghosts that have inhabited her body, but it could also be the isolde that she hides
the one who killed theophil, the one who joined manus all for one person, leading to millions getting killed/stormed away
isolde was a caged bird, and kakania gave her the key to leave. but the cage was all isolde knew, so of course she would fly back to a new one, even if logically she knows what will happen.
another interesting thing to notice is the description of this piece. it's by isolde, and it describes how she wants the libretto (essentially the opera, i'm not sure how else to describe it) in order to sing along.
singing is all isolde knows. it's both her escapism and her cage. she seems confused in this description, on why the music is not to be sung. she obviously cannot enjoy music without having the need to preform.
she also states that the music composition is beautiful, which i'm not sure if the piece itself is a atonality, but it definitely sounds very conflicting at times. the isolde that we have in the suitcase is the isolde "after" manus, so she of course is more in tune with the "real" isolde
now, i'm not a music expert or a isolde expert lol so i could be wrong, so feel free to correct or add on to this :) i ended up adding way more than i expected lol
