Learn English – A word/phrase for an action, which creates an equal and opposite reaction in another person

I have written the following piece (part fiction, part true story) and need to find a particular word to end the section in a way that makes the meaning clear:

I recently witnessed an incident in which a young child was ejected from a public library by a group of grown men. The boy had been studying books there for some time, and checking through the various reference materials, and as he'd done so, he had been asking the men questions about these texts.

Initially they'd indulged the boy, allowing him to speak freely, and coddling what they thought to be his deeply naive speech and questions. However, after a while he'd began to trouble them. The problem was that he kept getting up from his studies to ask them more and more questions, and about a number of topics about which either they did not have any interest, or which they did not care to answer.

What's worse is that he had also begun to ask some of his questions in a way that seemed to call the men's previous answers into doubt, and the men considered this to be very rude and discourteous. After-all, the men had studied there for a very long period, and the boy had not been studying at all as long as they had.

Slowly the men became angry at the boy, and after a while they went to get the manager, who was an old acquaintance of the men. Together they decided to give the boy one more chance: They told him he must go to the other children in the play area, and must teach each one of them something new, which they did not know before. He must then return to tell the men what and how he had taught, and they would judge how well the task had been completed. They said if he did this for two weeks, every day without pause or respite, they would consider allowing him to ask one or two more questions of them.

Some of the men believed this suggestion would placate the boy, while others secretly hoped to anger and upset him, that he would cause a scene, and they could ban him from the library.

As they'd anticipated, their suggestion angered the boy very much. He liked talking to the other children, but he also noticed that many of the men intended to fool him by setting themselves up as judges of his task, and felt that they would not accept his attempts to teach, and would look to find fault with him, so they could prove themselves better than he.

So instead, when the boy spoke to the other children, he asked them each a question which was similar to the questions he had asked the men. Then he wrote down the children's answers, and was careful to edit each of them subtly, so they became more like the answers the men had given, but subverted, so that they would see the flaws in the answers they had given to him.

When he took these answers to the men, they became indignant, and started threatening and insulting him. Several of the men shouted that he was an ignorant fool who could not even understand the difference between questioning and teaching, and they petitioned the manager to remove him from the establishment, lest he pollute other peoples' minds with his foolishness.

When the manager replied that he could not remove the boy simply for asking them questions, as long as he did so quietly and did not disturb the others at their reading, the men grabbed the boy by the shoulders, and jostled him out of the building. They did this in front of the manager, who saw the whole thing, but raised no objection — the men being his friends, after all, and the boy being a newcomer to the library, who he had no interest in supporting.

Afterwards I spoke to the manager and one of the men, who did not know I had witnessed the incident. When asked about it, one man said:

"He left in the most irrational of moods, just because we told him he was wrong. This really is very unfortunate, as he certainly did seem interested in learning."

To which the manager replied:

"Oh yes, very interested, though I think perhaps too sensitive at that age, to take criticism of the sort we more experienced sorts give out. A pity, really."

Later, as I was browsing through a passage in a very old book — a description of demons and angels, as I recall, I came upon a particular passage which reminded me of the incident. The passage noted that sometimes when demons look upon the polished face of angels, they see their own reflection, only slightly coloured by the light of the gods. And I thought that I had witnessed a small fractured version of that, where [A word/phrase for an action, which creates an equal and opposite reaction in another person] had conjured a demon in the eyes of the boy, which they had seen, and which had sickened them so… That it was their fear of criticism which caused them so much upset, and when the boy saw it in them, some small measure of it was also reflected in him.

My question then is this: what is the word or phrase which most closely resembles A word/phrase for an action, which creates an equal and opposite reaction in another person, and might work best in the passage above?

I have looked in a few dictionaries and thesauruses and the nearest I can find is a

Mirror Image Noun ‎(plural mirror images) Wiktionary

An image that […] appear[s as] if seen in a mirror; a reflection.

Which doesn't seem to fully communicate everything I'd like to sum up. Can anyone suggest a better word, that's specific to human communication, and which best fits with the rest of the piece?