If you are already overcome by fear, there ain't much to do! You're finished! The question is more what to do beforehand, so that you avoid "the moment when death suddenly seems near and the mind is overcome by fear."
So, what can you do to avoid it? First off, reflect on death. Reflect on every different way that you could die, just think them all up. Using the alphabet helps; reflect what can happen when you are in an airplane, what can happen when you are in a bus, a car, etc. And actually reflect, what would happen, how could you die? You know, you are walking down the street and a car swerves, goes up on the sidewalk and wipes you out. Imagine what it would feel like. Some of you have had intense pain in your life, some of you haven't had much. You have to imagine that pain, in maybe a different part of the body, or maybe magnified. OK, do it. Imagine what it would be like. Now, imagine every different type of death. And you actually imagine, "OK, this is super painful, my chest is going to be racked with pain." So you imagine, "What am I supposed to do when this is happening?" There is body awareness. Separate the mind from the pain, see it as a sensation rather than thoughts of "I am dying." Watch out for the fear thoughts. Watch the reactions in the body to the fear thoughts. How is this very much different to what I give every retreat on the fourth evening? The Unpleasant Physical Sensations technique. All you can do here is work with a little mosquito or a pain in your knee, but it is the same practice.
When you are reflecting on death in the meditation, imagine that something like that is going to happen, imagine what you have to do to combat the fear. Now, let's say you have done this over and over and you have actually thought about earthquakes, over and over. So, then what's going to happen if you're in earthquake all of a sudden? Maybe the thoughts that you trained will come up automatically and they'll blow the fear away and go, "OK, this looks like it's it. What am I going to do, how am I going to try to die peacefully?" But if you've never thought about it; it's classic that people who have never given much thought to death will die in much more agony than other people. If you never think about it, you're going to have the fear. If you do think about it you might not have the fear. It's almost simple in that way isn't it? Just hard to practice.
Just a word about reflecting on death, I wouldn't advise doing it every single sitting period. It can be a little too much. We also want to watch out for the emotional factor to move in. With reflection meditation we want to be very objective. We just want to see: "How could I die, what would happen, which parts of the body would have pain?" Try to stay with being more objective about it.