This is essentially Christ asking one of his dimensions if it wants to enter into the realm of creation. Can a dimension of Christ even give a meaningful free answer? Consider that Jesus was a dimension of Christ, extended into creation. The divine will of Jesus was a subset of the divine will of Christ, the Son of God; yet this subset of will, was truly free will. The Son of God asked Jesus to drink the cup of suffering, and Jesus was free to do so, or to do not.