How can I light inside a single solid object with shadows?

Lets say you’re standing in Cerebro with professor X and at the center sparks and flashes are going off. Now lets say that you need to create shadows coming from the center, and you need to have the shadows behave from any point inside Cerebro. How can I use a single light and get shadows casting from the center? If I use a point light I get odd striations along the inside of the walls. This appears to be a result of the shadow bias. If I leave it default I get these striations. But if I increase it they go away but I get odd shadows, they appear in the correct location but have different densities which make them look bad. This all seems to be some sort of limitation with lighting inside a single solid object.