Inserting that part was a risky choice. I recommend saving your game before that part. I'm sorry you had to start over. Below I explain how to overcome it:
.
.
.
.
.
.
.
.
.
.
the dark part is a corridor, if you go in the right direction for a while a dialogue will come out and then the music will drop and you will just have to wait, 10 seconds with the black screen and no sound.