It is impossible (not right) that a prophet should die outside of Jerusalem. In the Gospel narratives, we are accustomed to seeing Jesus enter into conflict with the religious authorities. Very seldom do we encounter a passage such as we read today in which we find the crowd concerned about Jesus’ well-being. Apart from some of the religious leaders, Jesus had been accepted as a rabbi and wonder worker, and many people had come to believe in him. They had also come to believe that Jesus had a messianic mission to fulfill (even if their understanding of that mission was flawed). To those who had come to believe in him, the hope of the community rested on Jesus’ shoulders, and they were not ready to let their hopes get crashed because of Jesus’ premature assassination. And so it was that they leaked to Jesus the plans Herod was harboring. But Jesus would hear none of it. ‘  Thank you for the heads up,’ Jesus told them, ‘  but I will not be cowed from fulfilling my destiny.’
Jesus understood his mission as a continuation of the ministry of the prophets of old. He was not going to run away from a prophet’s fate. Were all the prophets killed? I don’t think so. Were all killed in Jerusalem? Not really. But all the prophets fulfilled their missions. Jesus’ mission was tied to Jerusalem. His was to restore Jerusalem to its former glory (cf. Is 2:3; Zec 8:22; Micah 4:2:   all the nations will stream to Jerusalem for blessings). Jerusalem derived its glory from what she stood for. This is the glory that Jesus’ mission was fulfilling, and if it was going to demand that Jesus die in order for it to be fulfilled, so be it. 
We are reading this Gospel passage as the Church year is winding to a close. IN less than four weeks, the Church will be celebrating the Feast of Christ the King of the Universe. Although it is a feast that doesn’t celebrate the fate the befell Jesus in Jerusalem, it is a feast that sums up the entire life and ministry of Jesus. It is a feast that celebrates the mission of Jesus: salvation of the universe. Jerusalem is where the salvific mission of Jesus attained its culmination. Jerusalem, as it were, is where it was accomplished (cf. John 19:30: “It is finished.”) Jesus had to die in Jerusalem because it was in Jerusalem that Jesus, as the “seed” to new life in God, had to be “planted.”