Epicurus said that "death is nothing for us because every good and every evil comes from the senses and death is the lack of senses". Connecting the very deep meaning of death with the human senses removes any signs of the divine from it. Religions used to intervene with the physical death of a human body by claiming that the soul is immortal and continues to live in the afterlife. But this is a delusion. We are all products of matter and energy only. As contemporary science states, matter and energy are two sides of the same coin. We live in a materialistic space and time, in a Universe full of stars, planets, tiny particles and light.
Our existence is the result of natural selection and evolution of our genes. We start breathing from the first moment of our birth and this is the zero point in our life. But this is not the zero point of our Universe. Its approximate age is almost 13.5 billion years. Our solar system was formed 4.5 billion years ago. Our planet, Earth is not young. Lots of humans, animals, plants and other life forms have lived and died during its age. Even before the notion of religion, even before the first man looked up at the sky and thought about a super-powered creature (God) as the creator of everything, Earth was already there. Our planet is a small piece of rock moving around a star of medium size and significance and our solar system is somewhere in the middle of one of the spiral arms of our Galaxy, Milky Way. Milky Way consists of 200 billion stars, many of which are very likely to have planets of their own and the proper habitat for life. Milky Way is a part of the Local Group galaxy cluster. Clusters belong to Superclusters and we have counted almost 10 millions of them. Our Cosmos is huge! We are very very small and insignificant. Our life, our death means nothing to the Universe.
However, we experience a death-like situation every time we fall asleep. During our sleep, our system is partly working. We are breathing, the heart is beating, the muscles can move our body. Then, our brain is dreaming and our closed eyeballs are moving rapidly. This state of sleep is called REM. Between two REM phases, there is a Deep Sleep phase. During Deep Sleep, our conscious mind is at rest. No dreams, no contact with our environment, no senses. We cannot see, hear, smell, taste, touch. This is a lack of senses! Oh, I know what you think. This is a notion of death! And you are right.
Let's assume that the heart stops during the Deep Sleep phase. Almost all brain regions which have been shut down once we fall asleep could not be recovered. Imagine the brain functions as a row of switches: Once you close your eyes and fall asleep, your brain turns those switches off one by one. That's why we need some time to wake up completely. If your life-sustaining operations ceased abruptly, the switches will remain off. The brain will be clinical dead after some minutes. What would have happened to your memories? Unfortunately, our memory is not a flash drive. It looks like a computer RAM (instead of ROM). Plug out your desktop and voila! All opened application will close immediately and all data stored in RAM will be lost. Our system depends on energy. The brain works with electricity. No energy, no memory.
Once the memory is not functional, one cannot save the current state of one's mind. You cannot play a movie on your laptop if it's off. Thus, at the Deep Sleep state, a deadly incident will be like a plug-off. No matter what happens next, there will be no memory of the incident at all. You may recover it, exactly as you wake up from a very nice night sleep, but apart of some dreams, you will definitely remember nothing else.
Religious people tend to believe that during a near-death state, their soul leaves the body, has consciousness and can perceive its environment. Moreover, it can record everything, even the image of the "empty" body shown from above and recall the information later, if the body manages to survive. But, this is pure nonsense. If our hypothetical soul has a strange composition consisting of a substance other than matter and energy and can live without our body, then how does it interact with it? If my soul cannot interact with my body, then how could it have recorded our near-death experience? It would have been a foreign body instead; not me. On the contrary, if it can perceive our state and write it in our memory, then it consists of matter and energy and cannot live without it.
People prefer to keep a blind eye on such matters. That's why science works and religion not. Epicurus said it clearly: "death does not concern us because as long as we exist, death is not here. And once it does come, we no longer exist".