But on board the Messiah, Captain Tanner has come up with one last option. He calls the crew together to explain his plan. They can do nothing about the Beiderman fragment, but he believes they can still stop the main Wolf comet and give Earth hope for survival. Outgassing has created a very large fissure vent in the comet's surface leading well into its interior. As the comet draws closer to Earth, the sun will melt ice and widen the hole further. The Messiah has four nuclear warheads remaining.
If they can get these warheads into that Vent, the comet should be blown into fragments far too small to wreak the kind of catastrophic damage that the intact comet would cause. The crew has to get close enough to Earth to reach Houston Mission Control and get the manual arming codes for the remaining warheads, in order to synchronize the bomb timers properly. Tulchinsky and Simon know that the Messiah is dangerously low on both life-support and remaining propellent fuel.
It is not likely they can get into the cargo bay, or properly maneuver the Messiah for a second landing on the comet surface... much less get back off the surface once the warheads are planted. Fish's silence and grim expression, however, show that none of these are factors in his plan. It is a suicide mission; the Messiah making a kamikaze run into the comet's interior and detonating the warheads. All of the crew will perish. The crew is grim at this reality, but all quickly accept their pending fate.
The Messiah finally gets close enough to Earth to raise Houston Mission Control on audio. Fish briefly fills Hefter in and tells him to get the arming codes for the remaining nuclear warheads.
At the MSNBC news offices, final evacuations are underway. But there are seven people left in Caley's news team... and the last helicopter only has room for seven. As one of these must be the pilot, one of the news crew must be left behind for the helicopter to drop the others off on high ground in West Virginia before transporting Jenny to the Ark. Without any proper alternative means of deciding who must be left behind, straws are drawn. Beth draws the short stick, and quietly picks up her preschool-aged daughter, hoping for the best on the roads.
Leo has acquired a bicycle and arrives at the Hotchner house. The Hotchner family has evacuated, leaving their dog behind. Rushing to the garage, Leo manages to locate the key to unlock the motorbike. He takes it to search the highways to find Sarah. The panicked rush to get out of the city has brought traffic to a near standstill reaching for miles.
The news crew is rushing to board the helicopter. Jenny pauses to grab something from her desk. As she hurries to rejoin the remaining crew, they pass by the nursery. Beth is sitting there with her daughter Caitlin. Beth has realized the likelihood of successfully getting out of danger was very low with the frantic rush. She has resigned herself to her fate and gone to the nursery, hoping to spend her last few minutes holding and playing with Caitlin, despite assuring Caitlin that they will be safe.
Despite the frantic shouts of the other crew, Jenny simply stares at Beth for a long minute. Suddenly she grabs Caitlin out of Beth's arms and rushes madly for the helicopter. Beth rushes in anguish after her. But on the roof, Jenny thrusts Caitlin back into her mother's arms and announces that Beth is getting on the helicopter in Jenny's place.
Nobody can dissuade her from this; she refuses to let Caitlin and Beth die. Everyone stares in amazement, knowing that Jenny is giving up her very life... but they have no time to debate the issue. Beth and Caitlin are ushered aboard the helicopter and it takes off, leaving Jenny behind. As she stands alone on the rooftop, Jenny gazes at what she took from her desk... it's the photos Jason gave her.
Racing down the highway, Leo continues his search for Sarah. It is she and her parents who spot him first, calling out to him and honking. Chuck decides this time there will be no further arguing. He half carries, half-drags Sarah over to the motorbike, physically picking her up and putting her on the seat behind Leo.
He puts a motorcycle helmet on Sarah's head as Vicky works feverishly to attach a baby harness to Sarah's chest and slip the baby into it. Chuck tells Leo to hurry off and save himself, Sarah and the baby, getting to high ground. This time he and Vicky turn a deaf ear to Sarah's anguished cries of protest. As Leo races off, Vicky bursts into tears and Chuck hugs her.
Jenny, meanwhile, is shown pulling up to a beach side house... her family's house. She knows that Jason has gone here to spend his last moments before the tsunami strikes. She finds him on the beach, calmly staring out at the ocean. Saying that she lied to Jason about not remembering the day the photos were taken, Jenny finally makes peace and reconciles with her father. She hugs him and snuggles close, still frightened of her own impending death despite the decision she made to give her life up.
Time has run out. The Beiderman comet fragment breaks Earth's atmosphere and rushes for impact. Everyone for miles can see it race out past the coastline before it plunges deep into the Atlantic Ocean.
A titanic mushroom cloud roars upward and outward from the point of impact.
The skies turn dark; birds tossed helplessly about in the air as the tsunami begins to race inexorably toward the eastern coast.
At the Lerner beach house, Jenny gives a brief sob of fear before Jason pulls her head against his chest and closes his eyes.