I’m not sure hanging up a smartphone ever makes a “click” sound, actually. In fact, the phrase “hang up” seems altogether wrong for cellphones; it only really fits those ancient phones where you held the mouthpiece in one hand, and the earpiece was a separate thing that actually hung from a hook.
I don’t know if Abby was making a connection between parasitism and fanfiction, or between parasitism and vampires, or just between two fascinating instances of nesting objects and worlds within worlds. When I wrote it, I was only thinking of the last of those, but Abby may be more contemplative than I am.
The idea that scenes of violence and death should happen offstage is actually a tradition going back to ancient Greek plays. Shakespeare followed that rule more often than most present-day films, but still not much. Romeo and Juliet, for instance, has LOTS of onstage killing.