Here's something that didn't make much sense to me in Episode III.
Annakin was partial to listening to the Emperor, true...but when he found out the Emperor was a Sith, he was horrified and shocked.
What's more is when he returned and found Windu standing over the Emperor and having to make a choice, he argued that Windu wasn't making the right choice as a Jedi should. In that essence Annakin made the right choice, and stopped Windu from killing what appeared to him a downed opponent.
Of course that would be a hard choice, but HE didn't kill Windu, and he even had the point of being able to see Windu choosing a dark sided path.
So, though in a way he caused Windu to lose his defense, the only reason was because he stopped Windu from killing. At that point, even though Windu died...it was the Emperor who killed Windu...Annakin at that point could have followed up and perhaps tried to bring the Emperor in, or even fled.
Instead he submitted?
In fact he did so completely that he then goes to the temple and leads the charge to kill everyone there and kills the younglings himself?
Wait a second...did I miss something?
Annakin, only seconds prior to that was arguing with Windu about the proper thing a Jedi should do...yes part of it was self interest, but part of it was because it would also be wrong to kill a downed opponent (much like Luke did not succumb to his anger in RotJ and slay Vader because Luke was a Jedi).
What the Heck...why in the World...
In fact, Annakin didn't even try to kill Windu...and he didn't really incapacitate him...but he did make Windu lose an arm and his lightsaber.
In essence, Annakin had TONS of other choices than suddenly turn completely evil in opposition to how he had been acting previously...so what in the world did Annakin change in that split second.
If Annakin had fled, or let the Emperor be captured as he was telling Windu to do, so the Emperor could be tried...the Emperor would still be alive for Annakin to try to get the secrets of life from...
So why didn't Annakin keep to his original plan (as it seemed he intended when he went to Windu, and what he kept arguing with Windu to do when Windu was at the Window...) instead of suddenly just saying...time to kill that idea...and be one with killing innocents?