How do you make a monster spawn and then he leaves and you can hear a door opened.

[narutohokager]

If I understand you want to make a point when the player Walk Into a area the door will open any one is his?

If so, you might be putting a sound that shows the player to fear, you can find in your folder :

Amnesia - The Dark Descent\redist\sounds\react

And implement a command that lowers the sanity of the player :

GiveSanityDamage(10, true);