Near death experience
New age advocates and others use descriptions of people who have died briefly and come back to life (near death experience, NDE) as evidence of their views about spirituality.
The common aspects of these stories from people having had a near death experience are:
There is no need to attribute any of this to spiritual experiences in a spiritual realm involving interactions with supernatural entities.
A fact about the relationship between the brain and consciousness: Every tiniest conscious experience has a corresponding activity in the brain. Whether the brain generates consciousness or whether the soul triggers the brain activity; this question is not important for this topic.
Upon dying, the heart stops beating and the blood stops flowing; meaning, the brain nerve cells no longer receive oxygen and other molecules it requires for proper functioning. This includes glucose, which provides the energy needed to power endothermic chemical reactions — reactions requiring an input of energy.
So, the brain nerve cells function differently, triggering all kinds of unusual brain states. These correspond to unusual conscious experiences (when consciousness is present).
The eyes are involved in the tunnel experience. The eyes have increased sensitivity in a small circle in the front of your field of vision. If you restrict blood flow to the eyes, the peripheral vision will deactivate, becoming fuzzy and dark. Your brain interprets this as a tunnel.
In dreams (and hallucinations, and in people having various severe mental disorders), all kinds of wild unordinary events are experienced, involving interactions with all kinds of beings having all kinds of magical powers. With reduced blood flow to the brain, a dreamlike state occurs.
All of these aspects of a near death experience can be explained as already existing capabilities of the brain, and which are experienced in dreams, hallucinations, and visions. There is no need to look to any additional explanations to describe these.