These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Mitch, the Big Good, in accused in-story of having and using More Than Mind Control abilities just like the Big Bad. He's also accused of using a memetic weapon to make Thomas Muoka an Unperson. The Optional Canon origin story for him indicates that he was lying to his allies. Canonically, he sacrificed our dimension to Oul (not knowing it was inhabited). He also personally ran a Dystopia (albeit to save humanity) and wiped out human civilization at least 20 times. And in the end, he got to go home alive, unlike every single other named character. Suffice it to say, he has a bit of a spotty record.
It's said several times that a year and a half of total sensory deprivation should have (and in a sense, did) utterly destroy Anne Poole's mind. "Marooned" reveals that being restricted to 3+1 dimensions has a similar effect on Xio, cutting off nearly all of its senses except Mitch's meager five. So why doesn't Xio go completely insane (by its own standards, if not humanity's)? Maybe it/he did.
Word of God says Xio wasn't mentally affected because the subjective time was very short to him. All those millenia in our universe amount to only an eyeblink in terms of five-dimensional time.