From "Manual of Muad'Dib" by the Princess Irulan

Has he seen this moment in time? Jessica wondered. She rested a hand on her abdomen, thinking of the unborn daughter there, asking herself: Do I have the right to risk us both?
Chani lifted the spout toward Jessica, said: "Here is the Water of Life, the water that is greater than water— Kan , the water that frees the soul. If you be a Reverend Mother, it opens the universe to you. Let Shai-hulud judge now."
Jessica felt herself torn between duty to her unborn child and duty to Paul. For Paul, she knew, she should take that spout and drink of the sack's contents, but as she bent to the proffered spout, her senses told her its peril.
The stuff in the sack had a bitter smell subtly akin to many poisons that she knew, but unlike them, too.
"You must drink it now," Chani said.
There's no turning back , Jessica reminded herself. But nothing in all her Bene Gesserit training came into her mind to help her through this instant.
What is it? Jessica asked, herself. Liquor? A drug?
She bent over the spout, smelled the esters of cinnamon, remembering then the drunkenness of Duncan Idaho. Spice liquor? she asked herself. She took the siphon tube in her mouth, pulled up only the most minuscule sip. It tasted of the spice, a faint bite acrid on the tongue.
Chani pressed down on the skin bag. A great gulp of the stuff surged into Jessica's mouth and before she could help herself, she swallowed it, fighting to retain her calmness and dignity.
"To accept a little death is worse than death itself," Chani said. She stared at Jessica, waiting.
And Jessica stared back, still holding the spout in her mouth. She tasted the sack's contents in her nostrils, in the roof of her mouth, in her cheeks, in her eyes—a biting sweetness, now.
Cool .
Again, Chani sent the liquid gushing into Jessica's mouth.
Delicate.
Jessica studied Chani's face—elfin features—seeing the traces of Liet-Kynes there as yet unfixed by time.
This is a drug they feed me , Jessica told herself.
But it was unlike any other drug of her experience, and Bene Gesserit training included the taste of many drugs.
Chani's features were so clear, as though outlined in light.
A drug .
Whirling silence settled around Jessica. Every fiber of her body accepted the fact that something profound had happened to it. She felt that she was a conscious mote, smaller than any subatomic particle, yet capable of motion and of sensing her surroundings. Like an abrupt revelation—the curtains whipped away—she realized she had become aware of a psychokinesthetic extension of herself. She was the mote, yet not the mote.
The cavern remained around her—the people. She sensed them: Paul, Chani, Stilgar, the Reverend Mother Ramallo.
Reverend Mother!
At the school there had been rumors that some did not survive the Reverend Mother ordeal, that the drug took them.
Jessica focused her attention on the Reverend Mother Ramallo, aware now that all this was happening in a frozen instant of time—suspended time for her alone.
Why is time suspended? she asked herself. She stared at the frozen expressions around her, seeing a dust mote above Chani's head, stopped there.
Waiting.
The answer to this instant came like an explosion in her consciousness: her personal time was suspended to save her life.
She focused on the psychokinesthetic extension of herself, looking within, and was confronted immediately with a cellular core, a pit of blackness from which she recoiled.
That is the place where we cannot look , she thought. There is the place the Reverend Mothers are so reluctant to mention—the place where only a Kwisatz Haderach may look .
This realization returned a small measure of confidence, and again she ventured to focus on the psychokinesthetic extension, becoming a mote-self that searched within her for danger.
She found it within the drug she had swallowed.
The stuff was dancing particles within her, its motions so rapid that even frozen time could not stop them. Dancing particles. She began recognizing familiar structures, atomic linkages: a carbon atom here, helical wavering . . . a glucose molecule. An entire chain of molecules confronted her, and she recognized a protein . . . a methyl-protein configuration.
Ah-h-h!
It was a soundless mental sigh within her as she saw the nature of the poison.
With her psychokinesthetic probing, she moved into it, shifted an oxygen mote, allowed another carbon mote to link, reattached a linkage of oxygen . . . hydrogen.
The change spread . . . faster and faster as the catalyzed reaction opened its surface of contact.
The suspension of time relaxed its hold upon her, and she sensed motion. The tube spout from the sack was touched to her mouth—gently, collecting a drop of moisture.