Everyone's NIM is staked together. The pooled Albatross staking yield becomes the prize, and your deposit itself is never at stake. At draw time we combine our pre-published secret with the Nimiq chain's own block randomness (a VRF seed) and pick a winner weighted by how much you saved and for how long. Because our part was committed beforehand and the chain's part comes after, no one can steer it, and you can re-run the math yourself on the winner screen.