It’s never fully explained, but essentially they’re a machine that forces out your persona though unexplained techno-magic. The shape is just cheesy symbolism and is not integral to the summoning. Helps facilitate stressing the user out in a specific way and puts them in a mind state suitable for summoning a persona.
Legitimately surprised to see a cop holding another to such a reasonable standard. I’ve been so inundated with bad cops that I forget good cops really do exist out there.