Explosion never takes place with only one energy. Explosion is the union of two energies. If the explosion were possible with one energy, then it would have happened long ago.
It is as if you have a matchbox and you place a matchstick near it: they can lie like this indefinitely and no flame will result. No matter how small the distance between the two – half a centimeter or a quarter of a centimeter makes no difference – there will be no result. For that explosion the friction of the two is necessary; then only will you get fire. Fire is hidden in both of them but there is no way of producing it with only one of the two.
The explosion happens when the two energies meet. Thus, the sleeping energy within the individual must rise up to the sahasrar, the seventh and last chakra, and then only is the union, the explosion, possible. No union is possible except at the point of the sahasrar. It is just as if your doors are closed and the sun is shining outside. The light stays outside your door. You move inside the house up to the door, but still you will not meet the light of the sun. Only when the door opens do you come in contact with the sunlight.
So the ultimate point of the kundalini is the sahasrar. That is the door where grace awaits us. The divine is always waiting at this door. It is you who are not at the door, you are away somewhere inside. You have to come to the door. There the union can take place, and that union will be in the form of an explosion. It is called explosion because then you will immediately disappear; you will no longer be. The matchstick will have been burnt in the explosion though the matchbox will still be there. The matchstick that is you turns into ashes and merges into the formless.
In that happening you will be no more. You will be lost, you will be broken and scattered, you will no longer be. You will not be what you were behind the closed door. All that was yours will be lost. Only the one who waits outside the door will remain, and you will become a part. This cannot happen to you alone, by yourself. For this explosion it is absolutely necessary for you to reach up to the infinite cosmic energy. The sleeping energy within has to be awakened and made to rise upwards to the sahasrar where the cosmic energy awaits forever. The journey of the kundalini starts from your sleeping center and ends at the place, at the boundary, where you disappear.