Frankly speaking, I do not remember leaving. I found myself in this help-less painful state and enquired "Who is this guy who is so troubled?" And I found no one.
By the same token, who is it that sleeps? Who is it that awakens?
Perhaps there is only sleeping and awakening, without a sleeper or one who is awakened. In this respect, we are only pure consciousness, without an agent of consciousness.
"Once upon a time, I, Chuang Chou, dreamt I was a butterfly, fluttering hither and thither, a veritable butterfly, enjoying itself to the full of its bent, and not knowing it was Chuang Chou. Suddenly I awoke, and came to myself, the veritable Chuang Chou. Now I do not know whether it was then I dreamt I was a butterfly, or whether I am now a butterfly dreaming I am a man. Between me and the butterfly there must be a difference. This is an instance of transformation.
How do I know that enjoying life is not a delusion? How do I know that in hating death we are not like people who got lost in early childhood and do not know the way home? During our dreams we do not know we are dreaming. We may even dream of interpreting a dream.
Only on waking do we know it was a dream. Only after the great awakening will we realize that this is the great dream. And yet fools think they are awake, presuming to know that they are rulers or herdsmen. How dense! You and Confucius are both dreaming, and I who say you are a dream am also a dream. Such is my tale. It will probably be called preposterous, but after ten thousand generations there may be a great sage who will be able to explain it, a trivial interval equivalent to the passage from morning to night."
Chuang Tzu, Taoist Sage