So here's the reasons why Maurice lost some of these battles. Cancerous Rodent: He sees no threat in such a rat, so he just ignores it. Tundra and Agony: Doesn't count, he killed them in the last second. Hideous Mass: Obviously the mass is bigger and stronger than his younger bro, so he lost it. Gabriel First: HE ALMOST did it. If he wasn't using the laser he could just win it pretty easily. Druid: Same as Gabriel Insurrectionist: This guy was basically wielding another Maurice, so that's pretty unfair. V2 (both): That's just basically a V1 controlled by AI. No chances Leviathan: He was too far away from him, he didn't saw it. When the Leviathan attacked him, he was actually jumpscared, and froze in place Rude and Angry: Same as the normal insurrectionist. Gabriel second: Same as the first.
I think the enemies vs. enemies concept can be a whole lot better if Enemies can actually attack Flesh Prison and Flesh Panopticon. Right now, you've probably noticed that Maurice only attacks Flesh Prison's mini-Maurices and Panopticon's Lightbulbs, but not the actual prison directly. This could be a major change in the future if this worked out the way it would.
I do not think any other enemy defeats flesh prisons. Like, if you attack minions, prison stays undamaged, if you attack prison, it just overheals the damage