So, the Forerunners used all the combined Halo rings to wipe out all life in the galaxy, except the flood in order to kill it like they're Thanos or something, but my question is how? What exactly did the Halo rings do to kill everything? I think it's safe to say it wasn't an explosion, and it wasn't a wave of heat, possibly microwave energy, but then that would have EMP'd all the systems on the Rings. Gamma and X-rays could have worked, I don't know, I'm not a scientist, but does anyone know if there's a stated canon explanation of what sort of energy the Rings used to kill all life.