because I don't actually think my desire to pull off a narrative effect trumps a reader's need not to be further traumatised.

I thought that too. But then I thought: why does one have to trump the other? If you know you are liable to get triggery reactions from reading something traumatic, you should not be reading my stories, because they are as hazardous to the health as peanuts are to someone with a nut allergy. As the fan says in the second link: fandom is bake sale, not supermarket.