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* The prologue, showing the doomed crew of Apollo 1 banging on the hatch window, attempting to get out of the burning capsule. Then the glove goes back into the fire. In real life, perhaps mercifully, it took only 15 seconds for the astronauts to asphyxiate, long before any burns to their bodies.
* Marilyn's nightmare before the actual mission, which ended with Jim getting knocked into space. (She recently saw the film ''Film/{{Marooned}}'', depicting a stranded crew in space. On the commentary track, she asks her husband why he decided to take her to that particular film so soon before his mission.)
* [[WhamLine "Houston? We are venting something out into space."]] The one thing no astronaut EVER wants to see is their spacecraft bleeding out.
** "It's gotta be the oxygen." Followed by about a minute of horrified silence from Houston. THEY all know what this means.
* The scene where Haise and Swigert have started fighting. Not only are they using up more air (and producing more carbon dioxide) with all the shouting, but the prospects of a brawl in a ship whose hull is only a few millimeters thick is too horrifying to consider. Typically, astronauts are conditioned with NervesOfSteel and training to avoid or weed out personality conflicts. {{Justified Trope}}: Carbon dioxide poisoning can, among other gruesome things, cause erratic behavior. Of course, RuleOfDrama also applies (Lovell states in the commentary that the scene is entirely made up, and they never actually had any kind of fight).
** There is also a BlinkAndYouMissIt part in the scene where the crew is building the makeshift carbon dioxide filter. A quick point-of-view shot from Jack Swigert shows him getting tunnel vision from hypercapnia.
* When the crew finally disconnects from the Service Module for re-entry they finally get to see the extent the damage done by the blast. ([[https://upload.wikimedia.org/wikipedia/commons/4/43/Apollo_13_Service_Module_-_AS13-59-8500_%28cropped%29.jpg Actual picture from the mission]]) The music perfectly conveys how indescribably eerie it is to see the mass of broken equipment usually hidden under the panels that's twisted and gutted beyond repair, and fully appreciate just how close it brought three men [[CruelAndUnusualDeath to a grisly end, purely by accident.]]
-->'''Jim Lovell:''' We're getting our first look at the Service Module now... ''one whole side of the spacecraft is missing!'' Right by the high-gain antenna the whole panel is blown out, right up... [[OhCrap right up to our heat shield.]]
** Further, the implication of that comment is ignored for a bit, and the characters and dialogue skate past the last line of it, and focus on the damage to the jettisoned module, until Deke Slayton looks at Ken Mattingly ominously and simply repeats: "...The heat shield."
* In-universe, Jim's youngest son is scared of his father going into space, because of the disaster on Apollo 1. His father assures him that the hatch problem that killed the Apollo 1 astronauts has been fixed and can't cause problems anymore. Then he is told that there's been an accident on Apollo 13, and asks, "Was it the door?!"
* A RealLife consideration: You may thank NASA engineer [[http://www.universetoday.com/111424/remembering-john-houbolt-the-man-who-gave-us-lunar-orbit-rendezvous/ John Houbolt]], indirectly, for Apollo 13's survival. Early in the planning stages, NASA planned on using either the Earth Orbit Rendezvous or Direct Ascent, both of which would result in a monolithic single spacecraft departing Earth Orbit. In short, all three astronauts would head toward and land on the moon in this one vehicle. Houbolt, after reading about the concept of [[http://www.nasa.gov/centers/langley/news/factsheets/Rendezvous.html Lunar Orbit Rendezvous]], as developed by a Russian scientist, made several attempts petitioning NASA that Direct Ascent would make the lunar vehicle too heavy, EOR requiring more rockets, and overall more resource to develop and construct. While LOR had its risks, NASA eventually agreed. They designed two ''independent'' spacecraft: One an orbiting base with an earth-return command module, and a lunar vehicle designed only to land on the moon and return. Both vehicles had independent life support, propulsion, and guidance. As it turned out, NASA realized this advantage in case of an unlikely failure and had developed Lunar Module-as-lifeboat scenario training.[[note]]Some elements of the rescue plan [[CrazyPrepared had actually already been practiced]]. During Apollo 8, Jim Lovell accidentally deleted part of the Guidance Computer memory, requiring him to take star sightings and manually reprogram their position into the computer. On Apollo 9, the Lunar Module descent engine was fired while still docked to the Command Module, in the same manner as the course correction burns on 13.[[/note]] No one took it seriously until Apollo 13. If either the Earth Orbit Rendezvous or Direct Ascent were the choice, and similar problems occurred with the oxygen tanks that exploded, that single-vehicle idea would have ''utterly doomed'' this crew.
** Similarly, if the explosion had occurred after the landing rather than before it, the Lunar Module would no longer be attached, leaving the astronauts with no option other than to hope they got back to Earth before the batteries and oxygen supplies ran out. In such a scenario, the crew likely would not have returned alive. Subsequent Apollo missions equipped the Service Module with much larger rechargeable batteries, just in case the fuel cells ever failed again.
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