Satan's mind doesn't matter with the atonement. God's does. God is a JUST God. That justice can not be violated. We violated God's justice with our sin. God's law said that a penalty had to be paid which was death. But then, God's mercy and love paid the penalty for those who would believe. The atonement was all about Satisfying the demands of God's justice. Satan doesn't enter into it. He had no power over anything that God was doing and God owed him not a single thing in exchange for our freedom.
That is a very alien (and unknown) concept to the Church in the East. It is rooted in the human idea of justice. This juridical idea of God
Western Christians thought about God’s justice in the same way also; God, the infinite Being, was infinitely insulted by Adam’s disobedience. He decided that the guilt of Adam’s disobedience descended equally to all His children, and that all were to be sentenced to death for Adam’s sin, which they did not commit.
God’s justice for Westerners operated like a vendetta. Not only the man who insulted you, but also all his family must die. And what was tragic for men, to the point of hopelessness, was that no man, nor even all humanity, could appease God’s insulted dignity, even if all men in history were to be sacrificed.
God’s dignity could be saved only if He could punish someone of the same dignity as He. So in order to save both God’s dignity and mankind, there was no other solution than the incarnation of His Son, so that a man of godly dignity could be sacrificed to save God’s honor." [Alexander Kalomiros, River of Fire]
"He had no power over anything that God was doing and God owed him not a single thing in exchange for our freedom."
Right again, Blogger! :)