Why Should We Engage the Shadow?

In this clip a few ISC teachers debate a point: does one need to be psychologically whole in order to experience nondual states of consciousness? There are countless people who have experienced and stabilized non-dual states of awareness that are not "psychologically whole", there is no pre-requisite of psychological wholeness to experience to taste of Big Mind and Big Heart. However, ideally, a mature human being will also deal with those pesky shadow issues that inevitably follow everyone into enlightenment.