Stuck in the school of nightmares (chapter 15)

So this is my fourth playthrough of rejuvenation so far and I remember after the sequence upstairs having to return to the underground to put the 4 student brains to use with the broken machine. I have all 4 brains, checked each location multiple times and still the same cutscene plays when I interact with the green panel and the story doesn’t progress. Am I doing something wrong? It’s been a while since my last playthrough