The whole planet Earth has been made uninhabitable by a nuclear war. The people left alive only have a certain amount of time before they get radiation sickness. The only way to avoid a very unpleasant death is to kill oneself. The government aids this by making "suicide pills" available.
A good number of people arrange to kill themselves in what would normally be called accidents, but intentionally. A race car driver deliberately drives into a billboard to kill himself while at a racetrack.
A number of times while investigating the dead Alaskan town, the seamen encounter the dead bodies of people who "suicided" months before. The bodies are only partially decomposed, partly because the microorganisms that would normally rot corpses may also have been killed by the radiation. The bodies mostly look normal, but the faces have bloated and changed color. Families are shown gathered together on a bed, having "suicided" together; their faces are discolored and bloated grotesquely as well.
There are two scenes depicting people perishing in atomic blasts. One is a recording of a television newswoman, before, during, and after the moments she realizes a nuclear exchange has begun. This is shown on the computer in front of the woman's actual dead body, several months after her death.
The second scene depicting people perishing in atomic blasts is one in which the ship's captain imagine how his family died from an atomic blast. They look scared, there is a tremendous flash of light, the family drops to the floor to avoid the flames and fire that come in through the windows, the little boy and girl try to evade the flames as they get lower, but scream as they are engulfed anyway. Meanwhile, the wife screams for her husband who was not there.
A husband and wife take their toddler in to the main bedroom with them. They painlessly euthanize her with a hypodermic needle. They reminisce over her dead body between them, before taking their "suicide pills" themselves.
A city with famous landmarks is shown destroyed and in flames.
A man is shown trying to wash out a bleeding wound in his leg, in the shower, with blood running down his legs. He is shown later dying of radiation, which takes a while, until he is euthanized with an injection.
A number of times, radiation victims are shown vomiting.