This is a movie dream: 

... Realizing the error of her ways, that what the man had felt for her wasn't really love (which he too deeply regretted), the woman let herself fall into the vat of molten glass (in slow motion) with the artist who designed the cathedral, particularly its stained glass windows. Their bodies dissolved and gave the resulting sheets of glass a very delicate grayish hue. The artist had hopes for red, like the crimson that resulted in the past when he used (his own) blood. Nevertheless, when it was done and the stained glass windows were installed the effect was breathtaking and beautiful. The somber gray light that filled the cathedral was like dawn and dusk at the same time, and always.