Nightmare Fuel / Timeless

• Depending on how the series ends up defining the rules of time travel, the protagonists could either be altering a single, mutable timeline or jumping between an ever-increasing number of parallel timelines/ alternate realities. Both are terrifying to think about:
  • If the team is just ping-ponging back and forth between the present and the past in a single timeline, then every change they make in the past creates a present that grows more and more unrecognizable to them. Sure, they're missing out on pop culture references, and Lucy is engaged to a man she doesn't even know, but soon enough they're going to step on a butterfly and come back to a future where there's a moon colony, or one where the cold war got hot, or where they never existed. And they can't un-do their mistake by means of do-overs.
  • If the time travel turns out to be jumping between parallel timelines/ alternate realities, they've been doing so inadvertently and without a clue and taking the place of their alternate selves. The same goes for their alternate selves, who hop over to another timeline/ reality and replace their alternate-alternate selves. This could conceivable go on forever, or until they figure out how to get back to their original timeline/ reality.
  • If the team goes too far back in history, they could with some very minor actions create a situation they can't recover from. Returning to a present where the English language is entirely unknown would be a complete disaster.
• From the point of view of the mission control techs in the command center, the Lucy, Wyatt, and Rufus who get into the time machine aren't the ones who come out (and, from the team's point of view, the mission control techs they meet upon exiting from the time machine probably wouldn't be the same ones they saw before embarking upon their time-trip, either - just as Lucy's sister "vanishes" from existence after the team's first trip, so should various mission control techs be replaced with different-looking people). The trio that comes back from the mission always has a fantastic story about how history ''should'' have happened- the Hindenburg should have exploded when it was landing, John Wilkes Booth should have been the one to shoot Lincoln, etc... but these stories run counter to all historical records that exist in the altered time line.
  • Furthermore, the Lucy that gets out of the time machine claims to have a sister that never existed. This Lucy becomes increasingly distraught, even threatening to stop going on missions unless the sister only she can remember is somehow "brought back."
• There's also the idea that the people in the command center effectively cease to exist when the trio travel through time. Each time they travel, something is changed from minor (a new Sean Connery James Bond movie) to major (37 people who should have died on the Hindenburg survive to later beget children, grandchildren, etc.) and each alteration means the original timeline versions wink out of existence without warning, replaced by new versions.
  • There is also the possibility that either Flynn's or the team's meddling with history could remove the invention of the time-machine from the time-line. If, at that point, the team are in the past, there is a possibility (as they seem to be insulated from the ripple effect) that they could end up stranded in whatever year they're currently in.
  • Nope, not possible. Would, in the past, the Lifeboat suddenly vanish before the team's eyes? No. It has been established that the team and the Lifeboat (and its contents) are protected against the "ripple effect."
• It's openly stated that it is a major race to send the team back into the past before Flynn enacts his plan as at any moment, time could change and, for once, even the team would not even know how history has been altered around them.
• Just how powerful is Rittenhouse? Richard Nixon is terrified of what they can do to him and his family. That's right, one of the most ruthless and tricky Presidents of all time and he's nothing but a pawn in their schemes.
• 18th century medical practices. The word "infection" isn't even in anyone's vocabulary. Every ill is attributed to an imbalance in bodily fluids, which is remedied by bloodletting and injecting mercury into the patient's anus.
  • In general any trip the team makes before the mid-20th century is extremely risky should one or more of them get injured or sickened (as we saw in "Public Enemy #1"). And given that there are no quarantine protocols on either side of the trip, it's very likely that the team could bring back a disease the people in the target time period are completely unprepared to treat. By the same token, the team could bring back a disease from the past that modern medical professionals wouldn't be familiar with. Microorganisms from the present left in the past have millions of generations in which to mutate into something dangerous and untreatable with current medical technology.
• Christopher reveals the real reason she brought Lucy to dinner with Christopher's wife and children: In case something happens and Christopher's family is erased from history, she wants to be sure someone remembers them. In other words, Christopher is fully aware she could wake up one day and totally forget she had a wife and children and it clearly scares the hell out of her.
• No one seems to think that eliminating Rittenhouse wouldn't just leave someone/something even worse in its place.
• In "The World's Columbian Exposition" the team goes up against H.H. Holmes, the man so incomprehensibly evil the term "serial killer" had to be invented to describe him. He built a hotel designed to let him spy on and then murder anyone who checked in, and even occasionally pretends to be a fellow victim just for kicks. And of course, the worst part of all is this guy really did exist and did all this.
• The Sickening "Crunch!" of the father of the man who supposedly killed Wyatt's wife breaking his head open on a speed bump in "Karma Chameleon."
• The season finale has Jiya apparently okay after her first trip through time...until her eyes roll back and she briefly sees the view of the Golden Gate Bridge outside her window transform to it into a bridge under construction. She's shaken as she tries to figure out if she's seen the future or an alternate timeline.
• The shocking twist of the finale as Lucy tells Carol about Amy and how she's going to find a way to bring her back...only for Carol to reveal that she is "Rittenhouse stock," she's known all along with Lucy has been doing and is determined to keep up the company's plans to change history. Lucy's face expresses utter horror as she realizes that, while all this time she has been "protecting" her mom from the truth, her mother has in actuality been up to her neck in Rittenhouse's plans and doesn't care about saving another daughter as long as she gets what she wants.
• The 50 cent coin changes from Kennedy's profile to Richard Nixon's as of The Kennedy Curse, meaning one of the most venal and corrupt Presidents in US history is, in Rittenhouse's favored world, considered worthy of being on United States currency - which means they had him even more firmly under their thumb than in the 1970s in our world.
  • The date on the coin remains 1964. If the rules for US coinage remain the same, this means that not only was Nixon elected in 1960, he also would die in office before the end of his first term. Perhaps Nixon wasn't the stooge Rittenhouse hoped he would be, and they saw fit to get rid of him as well?
    • Season 1 saw Nixon terrified of Rittenhouse to the point of paranoia, with a heavy implication that everything he did was either Rittenhouse manipulation or his attempts to stop them. What does he know about their activities that has driven him so far over the edge?