A/N: There are very faint spoilers here for Feet of Clay. You may have to squint and tilt your head a little for the slash, but I don't think I have it in me to write anything more explicit about them. It's Vetinari, after all.
The knife trick's origins weren't complicated. Students at the Assassin's Guild found rather…interesting ways to pass the time, and there was nothing quite like a sharp object for livening up a boring game of Chicken. At the time, Vetinari found the whole thing rather tedious -- his own aim was excellent, which made the other students nervous, and Rust flubbed his throws so often that Vetinari had grown weary of patching his clothes.
After he'd become the Patrician, however, he found himself remembering the old knife game somewhat more fondly, and to his faint surprise he discovered that it was an enlightening -- and enlivening -- way of discovering certain small truths about those in his employ.
Wonse had closed his eyes as soon as Vetinari loosed the knife, the calm of his face betrayed only by the twitch just beneath his left eye and the vague trembling of his hands. But he didn't move, as Vetinari had known he wouldn't, and when Vetinari asked why, Wonse replied, "Because you told me not to."
Later, after Wonse's betrayal had time to play through his mind, Vetinari reflected that this particular response should have told him everything he needed to know about the man.
Vimes, of course, had stood ramrod straight, his eyes never leaving the knife. Vetinari preferred a throw with a wicked curve to it, and he could see the officer's mind clicking away, judging the arc and angle of the blade in order to calculate just where it would hit. He didn't move, nor did he flinch, although his jaw tightened when the blade entered the plaster just centimeters away from his left ear.
"Amazing how it seems to curve away at the last second, eh Vimes?" Vetinari said. "I imagine it must have seemed as though it would hit right between your eyes."
Vimes stared straight ahead, and unclenched his jaw enough only to offer a chilly, "Sir."
Vetinari allowed himself a tiny smile. "And yet you did not move," he continued. "Why was that?"
"Because," Vimes said, finally making eye contact. "You have very good aim. Sir."
Vetinari let him go. Later that evening, he read a report detailing the man's exploits at the pub, although Vimes being a drunk was hardly news. The Patrician was, however, slightly amused that the officer had been overheard to say, "Bloody great aim, yeah. The problem is, you never know what he's aiming at," before he'd staggered outside, thrown up in the gutter, and passed out.
For reasons known only to him, Vetinari never asked Drumknott to stand in front of the wall, an observation the clerk voiced one day after he'd dropped off one batch of reports and quietly whisked away those already read.
Vetinari looked up at the comment. His clerk was standing by the wall, looking thoughtfully at the dozens of small wounds left in the plaster. He'd once asked if Vetinari wanted them smoothed over, but the older man had declined -- he thought it would boost the morale of whoever was sitting in his office to know that he could be standing in front of the wall opposite.
"You've already had one knife ordeal in this office," Vetinari said. "I can't imagine you would be so eager for another."
Drumknott only offered his quiet, peculiar smile, and said, "This is different."
The Patrician raised an eyebrow. "Very well." He pressed a knot of wood on his desk, indistinguishable from all the other knots of wood, and a small panel smoothly slid out. The knife inside was small and silver, the weight carefully balanced for his hand. Its blade gleamed.
At Vetinari's nod, Drumknott moved so that his back was against the wall. He raised his chin slightly, his eyes meeting the Patrician's.
"You musn't move," Vetinari told him, and before Drumknott could respond, he threw the knife.
Drumknot didn't move.
He didn't move, didn't flinch, didn't even blink, just calmly held Vetinari's gaze as if they were doing nothing more than discussing the price of figs in Klatch. With something like horror, Vetinari noticed that he had allowed the knife much closer than usual -- a few more millimeters to the left, and his clerk would be missing an ear. But Drumknott hadn't moved, and as Vimes had noted years earlier, Vetinari had excellent aim.
The Patrician sat back, and steepled his fingers beneath his chin. "Impressive," he said dryly. "Most men watch the knife."
Drumknott shrugged, finally breaking eye contact. "I didn't need to," he said, that small, peculiar smile crossing his face again, and he gathered the reports from where he'd set them on the side table and padded softly from the room.
Vetinari said, "Hmm."