The Phowa technique involves the expansion of consciousness from being confined to the inside of the head and body - to fully embracing the entire external world. The 'inner' and 'outer' are fully integrated - but not limited to this 'integration'. This is reflected in Stages Four and Five of the Cao Dong Prince and Minister Schemata. Therefore, the individual consciousness can only pass through the Brahma-Chakra (at the top of the skull) at the moment of physical death if full enlightenment (and an all-embracing mind) has been realised by the practitioner beforehand. Charles Luk sought-out a Mongolian Lama to clarify this issue as most Chinese Ch'an Masters remained 'indifferent' to questions of 'death', 'dying' and 'after-life', etc. Although Phowa is interesting, and represents a realised state that is part of the full Ch'an enlightenment - it is not required as a separate teaching. How to transition between the apparent states of 'living' and 'dying' is clearly exhibited within the Ch'an Records Charles Luk translated. However, as individuals we are 'free' to seek spiritual instruction from whatever spiritual tradition suits our needs at the time of enquiry. For instance, it strikes me that 'humility' is the spiritual power behind genuine 'internal' martial arts - and represents a vast reservoir of universal power above, beyond and below the entirety of existence - and that's just my preference!