I would describe the conflict as exiting but always changing
The prologue's lines foreshadow the story's main plot: a tragedy between star crossed lovers. It revolves mainly around civil blood and how it will make the civil hands' unclean which is the main 'clue' of the ending of the story which is death.
Hope this helps!
Some of the elements which can be considered to be gothic in "the pit and the pendulum" are darkness, internal struggle, horror and terror experienced by the main character, lack of freedom, torture, etc.
