Season 1
- Mabel is introduced describing her fantasies of killing an intruder with a knitting needle. The first season ends with Bunny being killed by a knitting needle in Mabel's aunt's apartment, making Mabel a prime suspect in the murder.
- In the first episode of Season 1, the Arconia residents talk about being able to have the fireplaces on again since Tim Kono's death, as he's asthmatic. At the end of Season 1, Jan tries to kill the entire building by using the now-open fireplaces to gas them all.
- When Charles and Oliver are commiserating about Mabel's possible sketchiness, Vaughn in "Twist" compares Mabel to mistletoe, saying that "the very few thing that encourages people to kiss" is also deadly. That doesn't apply to Mabel, but it applies to both of the real Season 1 killers. Theo killed Zoe (albeit accidentally) due to their relationship (he had given her a ring and they got in a drunken argument when Teddy insisted he get it back). The Big Bad, Jan, killed Tim and tried to kill Charles because she was convinced that both were leaving her.
- At the end of "Twist", Teddy Dimas asks Oliver and Charles to make more episode "with lots of juicy twists and turns", and that he feels "like a proud papa." The next episode has the trio unearth the major twist that Teddy's beloved son Theo is Zoe's actual killer.
- At the end of Season 1, Cinda and Poppy are the first reporters on the scene while the trio are being led out post-arrest. Poppy already reads out the podcast name - "Only Murderers in the Building". How did they get there so quickly, and is Poppy just that good to make up a podcast name on the spot? No; Poppy murdered Bunny, and she had the title ready to go because it was all for the podcast anyway.
Season 2
- In "Persons of Interest", Howard convinces the trio to go to Bunny's memorial. Charles says that it's something only a guilty person would do. Howard convinces them to go because they could see other suspects. Shortly after that, Ursula tells the trio that "that podcast girl" has been sniffing around. Poppy is, indeed, Bunny's killer.
- In "The Tell", Oliver says that "it's hard to believe [he's] related to" Will's son, who's a mathlete. He's revealed not to be Will's father, and therefore not related to his grandson, at the end of the episode.
- In "Performance Review", we see Poppy White sit under a poster that says "Where is Becky Butler?" She's right there.
- Also in "Performance Review", Mabel and Alice talk about how Mabel loves being with Alice because Alice focuses on the present, not Mabel's past, while Alice is wearing Mabel's sweater. This foreshadows The Reveal at the end of the episode that Alice is using Mabel and dresses up as her as part of her art exhibit, reliving one of the darkest moments of Mabel's life (her discovery of the dying Bunny).
- In "Performance Review", Poppy corrects Cinda's pronunciation of Chickasha, Oklahoma ("Chick-a-shay", not "Chick-a-shaw"). This is because she's Becky Butler, who was a resident of Chickasha and so obviously knows how to pronounce it correctly.
- In "Performance Review", Poppy calls Mabel while she's on the subway to tell her Cinda's secrets (though they're not that exciting). As that happens, Mabel sees that Glitter Guy is watching her and he attacks her. With the revelation that Poppy and Kreps are working together, it becomes clear that Poppy timed her call then to distract Mabel from Kreps presumably trying to steal the bloody matchbook away from her.
Season 3
- In "The Show Must...", Oliver, Charles, and Mabel return to the Arconia after the supposed death of Ben Glenroy. As they get to into an elevator with Uma, she quips "At least you kept the body out of the building this time." At the end of the episode, they find Ben murdered for real, his body dumped in the elevator shaft.
