Out-of-Body Experiences (OBEs) can be brought up by the most diverse causes . Although OBEs are known and often reported to be more easily initiated by states of relaxation, it is lesser recognized that extreme pain can also trigger such experiences—without the experiencer being near death. Indeed, intense suffering triggered by physical trauma has been reported to force the projection of consciousness—a condition reported in the most unlikely circumstances by women giving birth.
Of course, one might wonder what would be the physiological relationship between such distant states (e.g., relaxation and pain) to bring about OBEs in such different circumstances. Nonetheless, whatever the mechanisms, the relationship of OBEs to pain, albeit rare, remains, even in cases where dissociative states are excluded - at least based on reported phenomenology. Such cases were reported by Edward H. Morrell (1869–1946), an American convict who became known for withstanding cruelty and torture during his stay at San Quentin, a San Francisco state prison.
In 1924 Morrell published The Twenty-Fifth Man, an autobiography describing his criminal activities fighting the corrupted railroad corporations of the western United States. The book, published after his pardon from life imprisonment, gave a stark insight into the extreme cruelty and unrestrained hatred suffered by inmates of the time but equally provided evidence of such OBE cases.
Morrell's suffering was triggered by a torture device called "the jacket", which was tightly laced to compress his whole body and induce extreme pain. If withstanding such a pain seems inconceivable, much less is how Morrell, subjected to such severe physical abuse, could report such inspiring accounts of mind projections, as the author referred to them. He described his experiences in the following way:
The cruelty became so common that Morrel seemed to become used to pain to the point where he could direct his "(…) mind to leave [his] body entirely and roam at will (…)". The described condition of such experiences as "never" appearing "other than real" is of note. Indeed, this suggests a differential condition to dissociative states which are equally known to occur under pain. Moreover, such an impression of objectivity was confirmed by the US governor of Arizona of the time, who wrote the book's introduction to substantiate some of Ed Morrell's perceptions of the outside world when Morrel was still in prison .
Two things are important to note. First, they are always confounders to any OBE explanations. In this case, although one cannot fathom the pain experienced by Morrell, and indeed the fact that pain can be associated with OBEs, it should be noted that the straight jacket may have induced a condition of pressure to the chest leading to insufficient blood flow to the heart muscle (myocardium) and may have increased oxygen deprivation. Another known cause of OBEs. The second point is more philosophical. Prison confinement operates through barriers to social interaction, prohibiting contact with other persons and the outside world. A condition often leading, as indicated by documentaries of the US system at least, to the degradation, humiliation, and mortification of the detainee's ego in unnatural ways. We may wonder how teaching to induce OBE in such a setting could be applied in rehabilitating inmates.
Last but not least. Whatever future OBE explanatory model is used to explain OBEs, such a model would equally need to be able to explain such circumstances, not mentioning all the commonly known others.
Sleep Consciousness Researcher,
Morrell, Ed; The Twenty-fifth man; New Era Publishing Co.; 1924.
Vieira, W. (1986). Projeciologia: Panorama das Experiências da Consciência Fora do Corpo Humano, Edição do Autor.
 My ongoing phenomenological research is currently looking at 28, mostly different conditions, known to have induced OBEs.  Morrell, for example, described his wife in detail, before having met her.