He’s been living in a stagnant ocean of malaise and that’s a problem because you can’t touch the bottom of the ocean and know there’s nowhere to go but up.
But there’s a light. And that light could potentially turn that ocean into a pool, and he’s swam enough to know how to get to the bottom of a pool and back to the top with his eyes closed.
It’ll hurt because you can’t breathe and your lungs will scream because for it to be a pool, you have to trust you’ll touch the bottom when you reach deep enough. And once you’ve reached there, you’ll kick up, shooting towards the light like a bullet to the brain.