I was listening to a knowledge tape by Sri Sri Ravi Shankar and heard a comment made by him on death. He says that Death is a choice that is given many times in your lifetimes and those who die choose to die at that time. It is like a choice given to you on whether you want to continue on this life time or do you want to take a break and come back later. This kind of ties in to the various stories and experiences that you read or hear from people who have survived accidents or experienced near death experiences. Most of the people have reported to have seen a tunnel of white light and then hear some voice saying that their time has not yet come. And so they return back to the same body.
Now is it the same for an enlightened master? An enlightened master is like a student who has graduated from the university. They do not have a fixed time or schedule on when to come to come or leave. They can come and go whenever they like. Once you are graduated from a college, you do not have to go to college and attend lectures or give attendance. But you can still go back to college and give lectures on your subject and help students graduate by sharing useful information. So an enlightened master is like someone who has graduated and comes back to college to help other student graduate.