Sri Aurobindo translates Mundaka Upanishad, Chapter 3, Section 2, Verses 5 and 6: Attaining to him, seers glad with fullness of knowledge, perfected in the self, all passions cast from them, tranquilised, — these, the wise, come to the all-pervading from every side, and, uniting themselves with him enter utterly the All. Doers of askesis who have made sure of the aim (or, ‘meaning’) of the whole-knowledge of Vedanta, the inner being purified by the Yoga of renunciation, all in the hour of their last end passing beyond death are released into the worlds of the Brahman.”
We see here a picture of the inner state of poise obtained by the wise who follow the practices outlined previously, who quiet their minds, quell the force of desire, and focus their attention on the shift from the egoistic individual standpoint to the divine standpoint. Through the renunciation of desires, they effectively disconnect the chain of cause and effect, and thereby abide in the consciousness of the Brahman and are not subjected to the normal mechanism of desire as the directing force for the process of rebirth.
Earlier the Upanishad links the desires to which one is attached as the attractive force that leads to particular forms of rebirth. Here, the Upanishad makes it clear that having practiced the inner renunciation of desire, there is no motive force left to drive particular desire-formed births. Any future rebirth then is linked to the intention of the divine in the manifestation, of which the individual is now a conscious and willing participant from the standpoint of the divine.
There are examples of individuals who lived a depraved life of thievery, distracted involvement in worldly enjoyment or debauchery, who had undergone experiences that were life-changing in their effect. After such experiences, which could be revelatory visions, near-death experiences, or simply the natural result of an increasing pressure to find new meaning in a life that seems empty and superficial, these individuals took up a focus on attaining to wisdom, looking within and finding the spiritual significance of life, and redirecting their energies to these pursuits and away from their earlier modes of life. They reached a status of dispassionate wisdom, and became examples of compassionate action focused on being living examples of a divine life. They attained to the status of Brahman and thenceforth acted from the divine standpoint rather than from the egoistic motives. The direction of their attention having been changed, the Upanishad indicates that they are now liberated and free from the pressure for rebirth.
Sri Aurobindo, The Upanishads, Mundaka Upanishad, pp. 193-210