Remaining calm allows you to write the scariest, most unsettling things. Often it’s nearly impossible to remain calm while writing. So how to do it?
View the things that happen in your story not as what you feel NOW, but as what your readers will feel LATER.
This way you can safely trudge ahead, more as an observer who reports than a participant who experiences.
This helped me many times to write through the darkest parts of my stories, the parts I didn’t want to go in, to experience again. Once I thought about simply observing them from outside, like I was watching a movie, and then simply writing down what I saw, I was able to descend into the creepiest, most terrifying corners of my mind…
(Did I scare you?)