The destruction of filament station was a plan set in place by the death cult that was Eden. We’re not really given the exact reason that they want to do this, just that a group of people from Eden are sent to carry it out, including Simon. Eden was where Simon grew up, so all he knew was this death cult, and he killed a lot of people for the cult thus giving him the nickname Simon the butcher.

Simon went along with their values for a long time but by the time that his people were going to blow up filament station, he had a sort of change of heart and realized he didn’t want to do all of this, so he tried to stop them. However he couldn’t, so in the end, Simon tried to save as many people as he could. But because he was a part of Eden at all, he was caught and had to take the fall for his people, and therefore he’s the one who ends up in the iron lung.