If you can throw the whole breath out, completely out so that no breath remains within, you touch a point of silence that can never be touched while the breath is in.
It is just like the ebb and tide: with every breath a tide of life comes to you; with every exhalation, everything ebbs - the tide has gone. You are just a vacant, empty shore. This is the use of this technique. SILENTLY INTONE A WORD ENDING IN "AH." Emphasize the exhaling breath.
When you exhale, the whole system changes and accepts death. There is no fear, you are ready to die. And one who is ready to die can live. Really, only one who is ready to die can live. He alone becomes capable of life - because he is not afraid.