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

I must get to the 'thopter , Yueh thought. I must put the ducal signet where Paul will find it . And fear struck him: If Idaho suspects me or grows impatient—if he doesn't wait and go exactly where I told him—Jessica and Paul will not be saved from the carnage. I'll be denied even the smallest relief from my act .
The Harkonnen guard released his arm, said "Wait over there out of the way."
Abruptly, Yueh saw himself as cast away in this place of destruction, spared nothing, given not the smallest pity. Idaho must not fail!
Another guard bumped into him, barked: "Stay out of the way, you!"
Even when they've profited by me they despise me . Yueh thought. He straightened himself as he was pushed aside, regained some of his dignity.
"Wait for the Baron!" a guard officer snarled.
Yueh nodded, walked with controlled casualness along the front of the house, turned the corner into shadows out of sight of the burning palms. Quickly, every step betraying his anxiety, Yueh made for the rear yard beneath the conservatory where the 'thopter waited—the craft they had placed there to carry away Paul and his mother.
A guard stood at the open rear door of the house, his attention focused on the lighted hall and men banging through there, searching from room to room.
How confident they were!
Yueh hugged the shadows, worked his way around the 'thopter, eased open the door on the side away from the guard. He felt under the front seats for the Fremkit he had hidden there, lifted a flap and slipped in the ducal signet. He felt the crinkling of the spice paper there, the note he had written, pressed the ring into the paper. He removed his hand, resealed the pack.
Softly, Yueh closed the 'thopter door, worked his way back to the corner of the house and around toward the flaming trees.
Now, it is done , he thought.
Once more, he emerged into the light of the blazing palms. He pulled his cloak around him, stared at the flames. Soon I will know. Soon I will see the Baron and I will know. And the Baron—he will encounter a small tooth .
There is a legend that the instant the Duke Leto Atreides died a meteor streaked across the skies above his ancestral palace on Caladan.
—the Princess Irulan: "Introduction to A Child's History of Muad'Dib"
The Baron Vladimir Harkonnen stood at a viewport of the grounded lighter he was using as a command post. Out the port he saw the flame-lighted night of Arrakeen. His attention focused on the distant Shield Wall where his secret weapon was doing its work.
Explosive artillery.
The guns nibbled at the caves where the Duke's fighting men had retreated for a last-ditch stand. Slowly measured bites of orange glare, showers of rock and dust in the brief illumination—and the Duke's men were being sealed off to die by starvation, caught like animals in their burrows.
The Baron could feel the distant chomping—a drumbeat carried to him through the ship's metal: broomp . . . broomp . Then: BROOMP-broomp!
Who would think of reviving artillery in this day of shields? The thought was a chuckle in his mind. But it was predictable the Duke's men would run for those caves. And the Emperor will appreciate my cleverness in preserving the lives of our mutual force .
He adjusted one of the little suspensors that guarded his fat body against the pull of gravity. A smile creased his mouth, pulled at the lines of his jowls.
A pity to waste such fighting men as the Duke's , he thought. He smiled more broadly, laughing at himself. Pity should be cruel! He nodded. Failure was, by definition, expendable. The whole universe sat there, open to the man who could make the right decisions. The uncertain rabbits had to be exposed, made to run for their burrows. Else how could you control them and breed them? He pictured his fighting men as bees routing the rabbits. And he thought: The day hums sweetly when you have enough bees working for you .
A door opened behind him. The Baron studied the reflection in the night-blackened viewport before turning.
Piter de Vries advanced into the chamber followed by Umman Kudu, the captain of the Baron's personal guard. There was a motion of men just outside the door, the mutton faces of his guard, their expressions carefully sheep-like in his presence.
The Baron turned.
Piter touched finger to forelock in his mocking salute. "Good news, m'Lord. The Sardaukar have brought in the Duke."
"Of course they have," the Baron rumbled.
He studied the somber mask of villainy on Piter's effeminate face. And the eyes: those shaded slits of bluest blue-in-blue.