How should one be mindful of death?

Namo Budhaya. In the Mindfulness of Death sutta Buddha says the following: > When this was said, the Buddha said to those mendicants: “The > mendicants who develop mindfulness of death by wishing to live for a > day and night … or to live for a day … or to live for half a day … or > to live as long as it takes to eat a meal of alms-food … or to live as > long as it takes to eat half a meal of alms-food … or to live as long > as it takes to chew and swallow four or five mouthfuls … These are > called mendicants who live negligently. They slackly develop > mindfulness of death for the ending of defilements. > > But the mendicants who develop mindfulness of death by wishing to live > as long as it takes to chew and swallow a single mouthful … or to live > as long as it takes to breathe out after breathing in, or to breathe > in after breathing out … These are called mendicants who live > diligently. They keenly develop mindfulness of death for the ending of > defilements. Buddha corrects wrong way to mindfulness of death. But as far as I see , a person who wishes to live as long as it takes to chew and swallo a single mouthful , is same as a person who wishes to live as long as as it takes to chew and swallow ....The translator of the text failed to point out the difference between the mendicant's way of mindfulness of death and Buddha's way of mindfulness of death. I will thankful if someone could explain this sutta in its true essence. My question is :How should one be mindful of death?