Perhaps what Jesus is simply illustrating is the "disciple is not above his master" principle. If even the incarnate God lived a life of servitude, how much more should His followers?
He describes the rulers of the Gentiles, and then establishes what things are like in God's Kingdom.
Granted, there is much more than that in Mark 10:45, the verse if full of the Gospel. However, the main point Jesus is trying to make in this particular instance seems to be similar to that of John 13:14.