Proof 8-Think about Near Death Experiences

Many Christians find the phenomenon of Near Death Experiences (NDEs) to be proof that "God" and the "afterlife" exist. As described in this article, an NDE contains these characteristics:
The sudden awareness that one has had a 'fatal" accident and not survived.
An out-of-body experience. A sensation of floating above one's body and seeing the surrounding area.
Pleasant feelings, calmness.
A sensation of moving upwards through a tunnel or narrow passageway.
Meeting deceased relatives or spiritual figures
Encountering a being of light, or a light (possibly a religious figure, i.e. Jesus, God, Buddha)
Being given a life review
A feeling of being returned to the body, often accompanied by a reluctance to return Things like heart attacks, near-drowning and severe loss of blood can all trigger near death experiences.
NDEs have been experienced by thousands of people and have been widely cataloged in a variety of books. Many of these books are "spiritual" or "religious" in nature.
What is not mentioned is that there is a drug called Ketamine that produces all of the elements of an NDE when it is injected into normal, non-dying people. In other words, an NDE is a natural, chemically induced state that the human brain enters. The trigger for an NDE is lack of oxygen to the brain and body. If you read scientific papers like these, you find that there is a completely chemical and completely non-spiritual reason for the features of every NDE.
Is this a direct proof that God is imaginary? No. However, it is a direct proof that the NDE (which many people use as "indisputable" proof that God and eternal life exist) has no supernatural meaning. We can scientificaly prove NDEs to be chemical side-effects rather than "a gateway to the afterlife" as many religious believers claim.