I reckon consciousness is a state, not a thing, so it can't be separate from the brain. Destroy the brain and consciousness is lost. I need a volunteer and a large hammer to demonstrate this. (I happen to like cats.)

So if 100 people look in the box at the exact same moment, they will all see the same thing. Consciousness must be a unity. Therefore it is impossible that the brain manufactures consciousness or all consciousnesses would see something different. That they can only see the same collapsed wave function, the same state, each and every one, each and every time, could only be because consciousness is a unity. If consciousness is a unity, it cannot be manufactured by the brain. If it is not manufactured by the brain, then consciousness is separate from the brain.

Or... they all see the same thing because the moggy is either dead or alive and can't be both.