Given the task definition and input, reply with output. Given scene/plot descriptions from movies or TV shows, and given a specific question about the scene, summarize the question into a title

In the finale of the first season of the revamped Dr. Who, we see Rose absorb the Time Vortex of the TARDIS and uses this power to not only evaporate the Daleks, but revive Jack. Due to this process, Jack becomes immortal. The question is, what was it about this resurrection that allowed him to be immortal rather than just giving him another chance at life?
How did Rose make Jack immortal?