As long as the rifle is hanging on the wall (the gnomes can time travel) at the beginning of the story, I won't mind if it goes off at the end. Deus ex machina

As long as the rifle is hanging on the wall (the gnomes can time travel) at the beginning of the story, I won't mind if it goes off at the end. Deus ex machina is only problematic if neither god nor machine has been properly motivated; when motivated by being shown rather than being told, so much the better! (compare https://uh.edu/fdis/_taylor-dev/readings/tolkien.html https://uh.edu/fdis/_taylor-dev/readings/tolkien.html ) Edit: note the importance of canon even (especially!) in fiction...