The real issue relating to exclusiveness is whether or not the Christian actually has a relationship with God, a presence of God, which non-Christians do not have. Apart from Christian spiritual formation as described here, I believe there is little value in claiming exclusiveness for the Christian way.
Dallas WillardJesus offers himself as God's doorway into the life that is truly life. Confidence in him leads us today, as in other times, to become his apprentices in eternal living. "Those who come though me will be safe," he said. "They will go in and out and find all they need. I have come into their world that they may have life, and life to the fullest.
Dallas Willard