That was Rosemary's death reflection wish. I think her wish was broader: Can you use your precious opportunity of being alive to develop your mind? When it comes to the moment of death specifically, if it's really sudden or if we're in a coma and are unable to control our mind, then there's nothing we can do. Buddhism does teach that at the moment of death, if you're conscious, if you are aware, you can actually use that moment for purification. You can use that precious little moment.
One way of looking at that moment of death is, "We're leaving... we're leaving." All of you have left your home country. When you got on the airplane, nearly all of you were excited to go - "Let's go back to Wat Kow Tahm! Let's go do another retreat!" You were really excited to leave your home country. Most people are not really upset about getting on that airplane. It's interesting: when you know you're going towards something that's better (in this case, coming for a retreat as compared to your normal life), something that you really want to go to, then there's no upset feeling about what you left behind. You let go easily. You don't care; you let go easily.
Now, can we let go that easily at the moment of death? It's not so easy because we're not too sure where we're going, right? But Buddhism teaches that if you live a good life; if you follow, in particular, the 5 Precepts they teach, trying to be more loving, kind and generous, then your next rebirth is going to be a good one, either as a human again or even in a heaven realm. So that feels kind of comfortable. If you can take that on as even a bit of a belief system - you don't have to believe it totally, but as a probability - then at that moment of death, you might let go more easily and then be able to to be reborn in an easier manner. Then, that moment would actually be used for the most benefit.
People get so crazed with what they want at the moment of death - "I'm dying. I don't want to die. There's a party Friday night. I don't want to go now" - they can't die peacefully. But if, rather than getting upset or angry, you're actually considering, "This is it, time to go. Hopefully I'm going somewhere better. Goodbye. Good luck," then we would be using those last moments in a very good way.