Captain Jack is the Face of Boe. Captain Jack cannot die. Captain Jack was once a Time Agent, or pretends to be one. Captain Jack wears a vortex manipulator. Dorium Maldovar sold River a vortex manipulator “fresh off the wrist of a handsome Time Agent.” Dorium Maldovar works with the Headless Monks from time to time. The Headless Monks decapitate people. The Face of Boe is a head with no body. Coincidences?--- ok mind blown. Never thought about this.