OBE's

One of my friends had an OBE (Out of body experience) some time back. We were killing time at a friends parking lot where he consumed marijuana soon after he had rum. He suddenly lost control and dropped down. He witnessed strange visualizations (like those in windows media player). He could hear everything we spoke but could not open his mouth to speak. He could see all of us and himself too, from a top angle, from a third person's view. Then he felt like he floated upwards and saw a tunnel of light. He saw a very peaceful and inviting world beyond the tunnel, calling him.
This is when it is said that the soul may totally leave the body.
Fortunately, he gained consciousness after some time.
This incident took place months back and he's still traumatized!

In my own findings, i came across a couple of interesting approaches.
In short, one is a realistic approach which says that the soul of a person leaves his body and travels through this tunnel, beyond which is a new world. This is how a person dies because of the soul departing from it. The other, scientific approach says that these are mere hallucinations which a person experiences when the oxygen supply to the brain is diminished (In intense or intoxicated conditions).