It does not matter if there is no order at 0.31$. Your sell order at 0.31$ will be created and market will not move down below this price until your order is fulfilled.
No, you are wrong. Imagine someone have put a sell order at $0.30, which order will be filled first? Certainly that's the less one, $0.30. My order will be there as it is and market will go further down.