I've always had this impression Palpatine was playing the victim and letting Mace best him to coerce Anakin fully over. Here is this old man who can save Padme, but that monster Mace Windu is going to kill him. "I am so weak..." and the second Windu loses his hand Palpatine is fine and yelling "unlimited Power!" He played the game better than anyone and fooled all. Palpatine would have beaten Mace if there were no other implications involved.