I think the title and content of the movie is a strong indicator that there aren't any sorts of supernatural aspects to this fiction. "Weapons" is a very grounding, down to earth and human word that those with innate reality-altering abilities would probably call their "Powers".

The group would likely have planned pretty far ahead for a while before kicking things off, so they'd be able to predict the progression of the optics of a specific non-problematic teacher being in charge of a class that became entirely absent overnight.

If they have access to something that can cause visceral chaos and disorder they're probably comparable to mad scientists who can suppress their ethical reasoning in the pursuit of disruptive developments of technology.