I don't think I've ever seen a spin on witchcraft and zombies like this

Does anyone know what the scene with the M16 over the crib was about? I'm thinking there's a tie in with school shootings and how transgressions/negligence at the home play into what ultimately ends up being an act of terror in schools.
On the surface level this was a supernatural horror/drama story. Just curious about the undertone and throughlines that the filmmaker also implemented in this for their broader point if that makes sense.
That was my initial take too. But it's hard to square with the rest of the movie imo. There aren't really any other visuals that connect to a school shooting motif.
So, on rewatches, I tried to see if anything else would connect. The only answer I have is that the house is like a gun, and the people she sends out to do tasks are her bullets. They come flying out of the house, head directly where she aims, and complete a task which usually involves some kinda violence.
So the M16 over the crib would symbolize that the house is like a loaded weapon, while the kids, parents, junkie, and cop are the bullets.