So Colin held the all-important words inside, speaking only to his empty soul.

This is probably linked to the idea of where the "empty souls" mentioned in the song actually go.

And let himself empty, heart, soul, and seed.

The ability to flee from suffering is a direct result of an empty soul.

And he does so while offering a chillingly fascinating tour of his own empty soul.

He screamed, a roaring tortured sound dredged from deep within his empty soul.

He is an empty soul, as conveyed by the look in his eyes.

With weariness, I hold, as they stared into each other's empty soul, or even with disgust.

The easy way of the Hungries, the way of the full belly and the empty soul.