Christ knew the pain would be temporary, maybe a few days for the worst of it,...................If I knew for a fact that my death would last for three days and then I would ascend to heaven, I would do everything in my power to start that chain of events.
First off I would think if you have ever been in any kind of pain you would realize that even a minute of excruciating pain is pretty darn unbearable. I would think that "knowing" what was to come did not bring comfort, and per the bible Jesus did ask to not have to bear what was to come. That speaks of separation between him and God(totally different awareness)....however to minimize the pain of a crucifixion seems kind of silly don't you think. If we believe what Christians teach than Jesus embodied the Christ "in the body"....and the body experiences pain and would be considered a sacrifice by Christ for sure. Again going by what they believe Christ could have said the heck with it....but didn't. Instead in mortal form chose to experience the pain and sacrifice at a level man could come to understand.
I also highly doubt if you thought it out for just a moment, you would not do everything in your power to get the ball rolling........sorry I just can't buy that
But coming back to Jesus asking to have this cup taken away.....the Gnostics speak of "Christ" having left the body of Jesus and that it was the man that experienced the pain and sacrifice. That during the baptism that Jesus received at an earlier date is when Christ entered Jesus body to spread the truth....or the way to the kingdom (which is within).
And just maybe...maybe the church back than watered down the truth of the resurrection.