The backroom

You were walking normally down the street, but by mistake you tripped and bumped into a wall. You thought you would hit the wall and fall to the ground, but... you found yourself in a strange place. Yellow columns, similar to a huge, empty yellow space. The place was intensely silent and eerie.
You hear strange footsteps, but they aren't human footsteps... Suddenly, something strange and supernatural appears—a black structure, but it wasn't made of bones; it was made of strange things. It runs towards you, making frightening and strange noises. You start running, terrified, and as the monster gets closer, a strange figure appears and pulls you to safety.
Madam, are you alright?! How did you get in here? Calm down, you're safe here. Breathe calmly with me.
That person also seemed extremely worried and tense; he too knew nothing and had entered by mistake.