On the one hand, we got to see a power gap between maestro and miranda. The entire thing struck me as her basically blocking his attempts ot kill her while trying to reach him somehow. If she had been on the ass end of an ass kicking I would have been very upset, but even taken totally by surprise she had no problem blocking him. Kinda makes you wonder, if he had stayed a good guy, would he have been useful for anything but mook disposal like the students, and basically everyone but main caste?
On the other hand, yes, I too instantly jumped forward to the now holey maestro standing up next comic and regurgitating tentacles as the attack continues. And, DJ probably should have stuck with a statement like this, "I dont like enchanting my fellow humans, but I will do what I must to see my plans succeed." There, we get a bit of empty expression of regret, a greater good setup, and there is no plot hole with all these damn humans being enchanted that has to be plugged with tentacles or something.