Few people think about the deeper aspects of their lives, marvelous though they may be (healing, nourishing, and functioning). Nothing, of course, is more important than Breath. My inner experience is that breath is fire. The beginning of breathing is closely harmonized with the beginning of thought. When one concentrates on a problem, the breathing slows down as the mind becomes one-pointed. This is even more pronounced in deep meditation. As thought becomes one-pointed, and then no-pointed, to the observer breath seems to have stopped. This is why, in coming out of deep immersion, one must consciously reconstruct his or her surroundings, and indeed, the world around us (as thought begins again). People who have not experienced this will not understand. If one meditates regularly at home, he or she will have inner experiences.
What part does bindu play in all this? To me that is the great mystery. Bindu has many meanings. It refers to the male semen (the creator of life). In itself bindu is a point without extension, containing all potential. Perhaps at the end of the kalpa, when all retreats into latency (with only the karmas surviving to revive active life), it is bindu that holds this potential.
Most of us are not suited to inquire into such matters. But to those who are driven to seek the Truth (not realizing that they are, themselves, the Truth), it is irresistible to delve into such matters. I warn against taking literally everything that is read. Scholars have a way of repeating what they have read, and after a while, there is a general acceptance of that as truth, much in the same way that the victor in wars rewrites the history to suit its own image and purposes. You must go within for answers.