He didn't teach anyone that. Maybe it's derivable from first principles; maybe a Thinker guessed it by looking at him. 

"Hello."

"Hi."

"I'll get the most awkward out of the way. We're terribly, terribly sorry about what we made you go through."

"He almost died."

"You also almost died, people shot at you. I very slowly and excruciatingly painfully almost died, though, yeah."

He sighs. "I know. I'll understand if you can never forgive us. It was—for the greater good." He shakes his head and sighs again. "I've said this phrase so many times it's almost completely lost its meaning, but it's true."

"It would have been right if you'd been right. But you didn't want to believe it."

"We didn't, it's true—but Eidolon was the best among us. He had been to every Endbringer fight, he had worked tirelessly to try to make this world as safe as we can—if we'd been right, then losing him might well have meant losing everything. But I'm not here to defend our actions. We were wrong. We're—I am sorry."

"We're pretty sure he wasn't doing it on purpose." Sigh.

Sigh. "I don't actually think it's the most unforgivable thing you did, even!"

He frowns. "It's not?"

"You are in general not competent enough to be making the decisions of which that was one example. Even when you found out about other worlds you missed that I was from one, with resources that could have saved us. You weren't planning an evacuation of this one even when it looked obviously doomed. There wasn't a good way to tell you about the Eidolon thing once we realized it, it could be someone else realized it ten years ago and sent an email that got intercepted by the spam filter and never noticed again - there is not in general a good way for Thinkers to confidentially or safely give you information they want you to have - there are innocent capes in prison because I couldn't be used for verification unless I wanted a full-time job patrolling for bank robbers. I could've eventually tackled the Endbringers with magical engineering and I was spending half my time doing translation work to pay for groceries, because there are no grants for prosocial activity without, again, full-time job on bank-robber patrol. You kept Lorica way past her birthday, time we could've used to save lives. You consistently failed to be an organization that people could trust or cooperate with, and you're so full of dishonest shenanigans and secret conspiracies that it was not hard to believe Eidolon was doing it knowingly and the rest of you covering for him, just like you cover for the power-buying thing and for Alexandria's second career."

He sighs again. "We were in fact planning an evacuation of this one when it looked obviously doomed."

"With no pilot emigration program, nothing apparently set up to move a lot of people..."

"No discussion with people who could've helped pull it off - and who were themselves often trying to figure it out, lots of effort wasted that could have been usefully corralled - if you were worrying about panicking people you could've just called it a dimensional colonization program, people'd be excited enough about that -"

"There are constraints, not only of resources, of which you are not aware. I understand this isn't satisfying, and I don't doubt you'll think I'm only using a lame excuse to not need to explain anything. I'm afraid that's the best I can offer."

"Ah-huh."

"Entertain the hypothesis for a bit. Suppose there's this shadowy organization that sells powers, with enough reach that you got the statistics you did from Damned Lies. It's probably sitting on resources beyond your imagination. It hasn't used those resources to turn the world into a utopia, and the reason for that is not greed. Assume the people in charge are not incompetent. Why would the world look like it does, if that hypothesis were true?"

"I've got guesses but we don't seem to be in a very information-sharing relationship."

"Do many of these guesses imply their next step is telling the two of you about all of their plans and resources and hoping you'll think of something they haven't?"

"One of them is 'you're following a thinker off a cliff and they can't see me', which would at least suggest that could possibly help."

"You're not the only person who's immune to many types of thinker, even if your defenses are more thorough than most. Eidolon himself was a blind spot to all thinkers I've met."

"I don't know how you decide who to trust but if 'exposed selves to additional personal risk after being nearly tortured to death for your fuckup in order to stop the Endbringers, otherwise quiet positive-sum researchers' doesn't cut it I question your algorithm."

Lorica is so great.

"If selflessly exposing oneself to extreme personal risk to stop the Endbringers were sufficient, we'd bring in every cape who goes to one of these fights. I'll grant you that the kind of selflessness needed to look past our mistakes and help us anyway is less common than that, but it still doesn't select for the kind of trustworthiness needed to help with the kind of problems said hypothetical organization faces."