This is by no means a comfortable scene, which is arguably the case throughout the movie.
The film also shows Dafoe’s character regularly standing and dancing naked in front of the light, which is also a pretty shocking sight.
One thing which does come up, however, is what drives Winslow to his madness.
It may be that the figurine he is holding is cursed, an accusation made by Wake at one point on seeing him with it.
Another is that the light, which seems to have a strange, tentacled creature living in it, is actually driving these men mad, or has its own curse.