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

Waste of moisture , she thought, knowing that this was Arrakeen thinking.
Paul stared around them, saw the rock scarp lifting out of the desert like a beach rising from the sea, wind-carved palisades beyond. He turned back as his mother lifted the bundle from the 'thopter, saw her stare across the dunes toward the Shield Wall. He looked to see what drew her attention, saw another 'thopter swooping toward them, realized they'd not have time to clear the bodies out of this 'thopter and escape.
"Run, Paul!" Jessica shouted. "It's Harkonnens!"
Arrakis teaches the attitude of the knife —chopping off what's incomplete and saying: "Now, it's complete because it's ended here."
—from "Collected Sayings of, Muad'Dib" by the Princess Irulan
A man in Harkonnen uniform skidded to a stop at the end of the hall, stared in at Yueh, taking in at a single glance Mapes' body, the sprawled form of the Duke, Yueh standing there. The man held a lasgun in his right hand. There was a casual air of brutality about him, a sense of toughness and poise that sent a shiver through Yueh.
Sardaukar, Yueh thought. A Bashar by the look of him. Probably one of the Emperor's own sent here to keep an eye on things. No matter what the uniform, there's no disguising them .
"You're Yueh," the man said. He looked speculatively at the Suk School ring on the Doctor's hair, stared once at the diamond tattoo and then met Yueh's eyes.
"I am Yueh," the Doctor said.
"You can relax, Yueh," the man said. "When you dropped the house shields we came right in. Everything's under control here. Is this the Duke?"
"This is the Duke."
"Dead?"
"Merely unconscious. I suggest you tie him."
"Did you do for these others?" He glanced back down the hall where Mapes' body lay.
"More's the pity," Yueh muttered.
"Pity!" the Sardaukar sneered. He advanced, looked down at Leto. "So that's the great Red Duke."
If I had doubts about what this man is, that would end them , Yueh thought. Only the Emperor calls the Atreides the Red Duke .
The Sardaukar reached down, cut the red hawk insignia from Leto's uniform. "Little souvenir," he said. "Where's the ducal signet ring?"
"He doesn't have it on him," Yueh said.
"I can see that!" the Sardaukar snapped.
Yueh stiffened, swallowed. If they press me, bring in a Truthsayer, they'll find out about the ring, about the 'thopter I prepared—all will fail .
"Sometimes the Duke sent the ring with a messenger as surety that an order came directly from him," Yueh said.
"Must be damned trusted messengers," the Sardaukar muttered.
"Aren't you going to tie him?" Yueh ventured.
"How long'll he be unconscious?"
"Two hours or so. I wasn't as precise with his dosage as I was for the woman and boy."
The Sardaukar spurned the Duke with his toe. "This was nothing to fear even when awake. When will the woman and boy awaken?"
"About ten minutes."
"So soon?"
"I was told the Baron would arrive immediately behind his men."
"So he will. You'll wait outside, Yueh." He shot a hard glance at Yueh. "Now!"
Yueh glanced at Leto. "What about . . . "
"He'll be delivered to the Baron all properly trussed like a roast for the oven." Again, the Sardaukar looked at the diamond tattoo on Yueh's forehead. "You're known; you'll be safe enough in the halls. We've no more time for chit-chat, traitor. I hear the others coming."
Traitor , Yueh thought. He lowered his gaze, pressed past the Sardaukar, knowing this as a foretaste of how history would remember him: Yueh the traitor .
He passed more bodies on his way to the front entrance and glanced at them, fearful that one might be Paul or Jessica. All were house troopers or wore Harkonnen uniform.
Harkonnen guards came alert, staring at him as he emerged from the front entrance into flame-lighted night. The palms along the road had been fired to illuminate the house. Black smoke from the flammables used to ignite the trees poured upward through orange flames.
"It's the traitor," someone said.
"The Baron will want to see you soon," another said.