/Mu/ I need your help to find a Mozart's fugue by description

Here's another quotes

>The melody seemed at first to be floating up the staircase to wards me, briefly marking time before it dashed in desperation on to the landing - that was when I could hear the short moments of quietness between its sounds, Then the pianist’s fingers picked up the tune, set it back on the steps, and the whole thing was repeated one flight of stairs lower.
...
>I suddenly understood that every melody has its own precise meaning, and that this was one of the proofs of the metaphysical impossibility of suicide - not of its sinfulness, but precisely of its impossibility. And I felt that all of us are nothing more than sounds drifting through the air from the fingers of some unknown pianist, nothing more than short thirds, smooth sixths and dissonant sevenths in a mighty symphony which none of us can ever hear in its entirety.
...
>‘I am attempting.’ he replied, ‘to play a rather difficult piece of music. But unfortunately it was written for four hands and I am now approaching a passage which I shall not be able to manage on my own. Perhaps you would be kind enough to assist me? I believe you are acquainted with the piece in question?’

>>74070753
https://www.youtube.com/watch?v=xXnlJcM_Cb0
just a shot in the dark

https://www.youtube.com/watch?v=C5M9KsJ3qRM