The answer to this requires some background knowledge about Bible story.
There was a king name Nebuchadnezzar, who had ordered his citizens to worship the idol of gold. If someone failed to do so, they would be put in furnance.But three men Shadrach, Meshach and Abednego refused to do so. Furious with rage, king Nebuchadnezzar ordered them to put in furnance seven times more hotter than usual. It was so hot that the army men who had tied Shadrach, Meshach and Abednego and taking them to furnance died of fire. But Shadrach, Meshach and Abednego did not die, and no harm was occured to hem. Seeing this, king Nebuchadnezzar appreciated their Gods saying that their God truely sent an angel to save these men.
In the context of this book, Ann Simpson is playing the role of Shadrach. So the students tie her to chair, and put her in radiator room, and they forget about her. When the church started, they go upstairs. As they were fatherless and teacherless, there was no one to remind them of Ann SImpson.
After hearing banging noise from radiator pipes, someone brought Ann Simpson. She was burnt, and she told she wont ever play the role of Shadrach again.
To this, Jim commented that if Eunice Ann Simpson had faith in God just like Shadrach, she wouldn’t have got burns