“Between the third and the fourth layers of ether it is a bit tricky. You can slip into the fourth layer and not be able to come back. You are drawn into a merger and lose the separateness of normal experience.
That is why in the ambrosial hours of the morning when people of God leave their body to bless all, their physical bodies are always guarded. At that time any imbalance can create a disturbance and they may not return.” Yogi Bhajan
(via Ram Anand)