Clone Cadets - S3-E1
Trivia: Commander Colt watches Domino Squad do their test and says, "Start The Citadel challenge, version THX, variable 1138," which is a reference to THX 1138, another film by George Lucas.
Trivia: When Sy Snootles kills Ziro the Hutt, he mumbles "What a world," a reference to The Wizard Of Oz.
Answer: I guess that 1) the King assumed that Ventress' droids were meant to capture the Jedi, not kill him outright. When she yells at OOM-224 to shoot Yoda, she evidently failed that expectation. 2) Sending out a bunch of Droidekas after it is plain that Master Yoda has clearly won is not a sign of good sportsmanship, either.