Bisects a man faster than a human eye could follow

"My Lord," Grammel babbled desperately, rising from the bench, "if I—"

Faster than a human eye could follow, Vader's lightsaber was up, activated and moving. Grammel's
slashed form pitched wildly, stumbled backward and tumbled over the side of the crawler. There was a
lull as the stunned driver looked on in terror.

Splinter of the Mind's Eye, Chapter XII, 115