All activities of the antarā-bhava are primarily governed by the karmic power of the manas

The antarā-bhava also possesses the six consciousnesses, but their operative force is relatively weaker, not as strong as in a human body. Because the antarā-bhava is a manifestation of karmic force, its material body differs greatly from a human body, and consequently the mind consciousness, which depends on the material body, has weakened functions of thinking, analysis, and judgment. With the manas no longer restrained by the mind consciousness, karmic habits will manifest completely. If the manas's afflictive habits have not been transformed, if precepts, meditation, and wisdom have not been cultivated, if it does not accord with wholesome dharmas, if merit has not been developed, and if the three fetters have not been eliminated, one will certainly be bound by afflictive fetters and take rebirth in the three evil destinies. All activities of the antarā-bhava are dominated by the karmic force of the manas: if the manas is wholesome, one takes rebirth in a good destiny; if unwholesome, one takes rebirth in an evil destiny; or one takes rebirth in accordance with the manas's power of aspiration.

Why is there no mind consciousness during the stage of imminent death? Because the tathāgatagarbha is about to depart and gradually withdraws the seeds of the four great elements, no longer transmitting them outward; the functions of the five faculties can then no longer be sustained, the six sense objects can no longer be conveyed inward, the conditions for the arising of the mind consciousness are incomplete, and the mind consciousness ceases to arise. As less and less of the six sense objects is transmitted, the six consciousnesses grow increasingly faint until they finally cease.