All thoughts hold as their intentionality objects or relations to objects, from the external world. Even the most far-fetched world or monster is but a mismatched representation or opposition of our own world. Under extreme pain, ones ability for imagination, including desire, wants, needs, and all other bodily and thought processes constrict to the point where there is nothing but pain. It is not that mind has ceased to exist, only that both mind and body have enveloped one another to the point where both are the same manifestation, both have become pain. As the reality of extreme pain, pain itself becomes the only reality.
Extreme pain is ultimately the complete absence of imagination.
Pain and imagining are the reciprocal relations that make up our existence. The more pain experienced the less imagination present. The same is true for imagination. As pain begins to gain objects, to reconstruct its world and the ability to objectify itself, pain dissipates and imagination begins. For example, a person becomes so impoverished that pain begins.