I was co-supervising a PhD student who had a difficult relationship with their primary supervisor, to the point where they couldn't compose an email out of fear of retaliation and dismissive anger. One evening I was working late and went down the corridor to print something. I saw the primary supervisor standing at the student's door, arms folded. As I printed, I listened to the tone of the conversation as I could not hear the words. I decided this was not a healthy moment - the supervisor was being intimidating and the student was backed into a corner, alone in an empty office after hours. I went into the room and put a random book on the student's desk, saying "This is the book we talked about, I forgot to bring it to you earlier". The student played along, and me being physically between them disrupted the intensity of the situation. I walked the primary supervisor away from the room. After this, I read up on bystander intervention because it was needed in that situation. To my mind, the abuse of power was that the supervisor was ignoring everything that made them intimidating and powerful in that setting, including the very evident fear of the student. The student subsequently went on leave and, upon returning, requested a change of supervisor.
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