To prevent any money from leaving your account, you can pause all payouts. First, navigate to the Funds tab in the main Slush Pool menu. On the right side of your screen at the top you’ll see a button to Pause All Payouts

When you click the button, a popup will appear and you’ll be asked to confirm that you wish to override your payout rules and stop all payouts indefinitely. To proceed, just click the Pause button.