Audio problem: When Anakin says, "What? Uh-oh," his mouth does not move. He just looks shocked that his lightsaber could not cut The Zillo Beast.
Continuity mistake: When Mace and Ponds have the exchange that ends with the Jedi General dropping "I have a bad feeling about this", Ponds' kama (kilt) has a blue border instead of the usual maroon to match his armour. (00:08:43)
Continuity mistake: When the Chancellor is being briefed on The Zillo Beast, Rex's kama is missing. (00:14:12)
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.