When Jesus was on the cross, He took the stain of sin upon himself and was punished by the Father for it. Here you have God punishing God. It makes for a strange mental picture. How does God turn his back on himself?
Personally, I believe that Jesus never stopped being God. He left his glory and power in heaven when He took on the body of a man, but the nature of who he was never left him. God in the flesh. He still has the spirit of God within the fleshly body, so he is still wholly God even though he left his power and majesty behind.
God the Father would have punished God the Son spiritually even though the body went through physical torture and torment. The physical reflects the spiritual but they are not the same. While we can identify with the cross, we can not understand fully the punishment and sacrifice that Jesus would have taken since we are not spiritual.