Explore the basement

You descend to the basement and you avoid the encounter with the creature (or person) in the house. Quietly, you use your phone to get some light and you walk for a few minutes surrounded by darkness and the smell of putrid flesh.
You are completely sweated, and into the darkness, you listen to slow, heavy steps and a sniffing sound.
A monster is lured by your smell?

You find a spiral staircase with a buzzing sound that leads to a room upstairs with a greenish light, also you notice a single door, marked in smeared, bloody letters that spell out "Don't open."