Cisco's faith in his ability to fill Barry's shoes as Team Leader is upended when he learns of the murder of someone close. Meanwhile, Killer Frost trusts no one except herself to hunt down the dangerous Ramsey Rosso.
- Arson, Murder, and Jaywalking: According to Breacher, breach psychosis causes hallucinations, blackouts and dry mouths.
- Big Damn Heroes: Ralph clears part of the rubble just in time to save Joe and Nash before they suffocate to death.
- The Big Damn Kiss: Cisco and Kamilla finally share a kiss despite not being able to express the happiness to have each other.
- Big Entrance: Instead of the usual portals, Breacher arrives by slashing through the dimensional walls with a large dagger to tear his way into Earth-1 right in Cisco's bedroom.
- Bittersweet Ending: Gypsy's killer has been captured and imprisoned, Breacher has fully reconciled with Cisco, Cisco and Kamilla's relationship is stronger than ever, and Barry has full confidence that Cisco can lead the team after the former's fated death. However, Gypsy really is gone for good, but Nash at least seemingly provides a "Ray of Hope" Ending that Barry's fate will not necessarily be like hers.
- The Bus Came Back: Breacher and Norvock.
- Bus Crash: Breacher returns to Cisco's bedroom in Earth-1 to mourn Gypsy's death.
- Central Theme: Having faith in other people.
- The Chains of Commanding: Cisco struggles with the responsibility of being a leader, comparing himself to Barry too much. He comes around at the end of the episode, however, not even needing the B.A.R.I. AI anymore.
- Clear My Name: Cisco’s subplot in the last third of the episode.
- Close-Call Haircut: Cisco's (second according to Camilla) blackout caused him to almost literally give himself one.
- Cold Open: The first scene shows Cisco being arrested. The episode than goes back in time a little for a How We Got Here.
- The Cracker: Echo is a multiversal version.
- Continuity Nod: Iris asks the B.A.R.I. what Barry's favorite food that she makes him for breakfast is. Barry and the B.A.R.I both respond, "banana," which is reminiscent of when Barry pretended to enjoy Iris's pancakes, but Iris, after having tried and failed to eat her own pancakes, announces that she is going to make Barry a banana.
- Creepy Monotone: Echo's manner of speaking is extremely creepy.
- A Day in the Limelight: This episode is centered on Cisco. In addition, the supporting characters (Frost, Ralph, Joe and Nash Wells) have more screentime than the protagonists Barry and Iris, who appear only in the first and last scenes of the episode.
- Deus Exit Machina: Barry and Iris are taking a vacation before he possibly dies in the Crisis.
- Dropped a Bridge on Him: Gypsy, a supporting character with dozens of appearances since season three, was murdered off-screen.
- Easily Condemned: Shortly after seeing Echo murder Gypsy in one of his memories, Breacher is quick to believe Cisco committed the deed.
- "Eureka!" Moment: Ralph trying to convince Killer Frost to trust her friends makes her think that there is someone for Ramsey to trust: Caitlin.
- Expecting Someone Taller: Agent Zak Zeal says this to Cisco.
- Fake Shemp: The flashback scene where we actually witness Gypsy's death obscures her face, to hide the fact that it's not Jessica Camacho.
- First-Name Basis: In a moment of heightened emotions, Cisco calls Breacher "Josh." Also doubles as a bit of O.O.C. Is Serious Business.
- Frame-Up: Echo makes it look like Earth-1 Cisco was Gypsy's murderer. He hacked Cisco's white noise machine to cause him to sleepwalk, thus making it seem like he killed Gypsy while in this state.
- Fun with Acronyms: Cisco calls the A.I. he based on Barry's brain patterns "Barry Allen Replicated Intelligence", or "B.A.R.I." for short.
- Hoist by His Own Petard: Cisco defeats Echo by turning his own gun on him.
- Internal Reveal:
- Breacher learns Cisco took a metahuman cure to remove his powers.
- Joe tells Nash about Barry's fate in the Crisis, letting Nash realise Team Flash have encountered the Monitor before.
- I "Uh" You, Too: Cisco Cannot Spit It Out regarding his feelings for Kamilla, but at the end of the episode she gently tells him she feels the same way.
- I Work Alone: Killer Frost, due to considering not seeing Ramsey's true self her fault. Ralph tries to talk her out of it, but she still insists to continue alone for now.
- Killed Off for Real: Despite vaporization being inherently a Never Found the Body case that leaves one expecting her to pop up later, we are able to witness Gypsy's final moments. As of this episode at least, it seems she's gone for good.
- Lampshade Hanging: Like Barry and Cisco before him, Joe takes notice of Nash's importance in coming events. It's practically become a Once an Episode Running Gag by now.
- Like a Son to Me: Breacher admits to seeing Cisco as one, giving him time to set his affairs in order before turning himself in.
- Locked in a Room: Joe and Nash get trapped in a cave-in underneath Central City.
- The Missus and the Ex: Or rather, Kamilla meets the father of Cisco's ex. However, he quickly takes a liking to her, and mentions that she and Cynthia would have also hit it off well.
- Never My Fault: Nash is quick to blame Joe for the ceiling collapse, and later the explosion sapping most of their air. As Joe points out, neither event happens if Nash just tells Team Flash what he’s looking for - the explosion is even more egregious, as Joe barely gets to say “Don’t” before Nash fires his blaster.
- Nice Job Breaking It, Hero: Joe grappling with Nash sets off his blaster and brings down a part of the ceiling, trapping them. Later, Nash tries to blast them out, which causes an explosion and reduces the oxygen level further.
- No Body Left Behind: Cynthia's body gets completely vaporized by the transonic-demolecularizer.
- Noodle Incident: Cisco's blackout in this episode is his second one. According to Camilla he already had one the previous night.
- Offscreen Moment of Awesome: Ralph's quick and simple yet effective detective work that allowed him to find and rescue Joe.
- O.O.C. Is Serious Business: Breacher doesn't shows his usual aggressive behavior when he goes to Cisco's bedroom, because he is distraught with his daughter's death.
- Out-Gambitted: Once Echo realized that he looked like Cisco and that Gypsy breached him to Earth-1 as a result of this, he attempted to pull a Frame-Up on Cisco by planting the gun that he used to kill her in his work area and hacking into Cisco's white noise machine to cause him to sleep walk, thus suggesting that he killed Gypsy in his sleep. However, the real reason Gypsy breached him to Earth-1 was because she figured that Cisco would be smart enough to eventually deduce that Echo is an evil version of him from an alternate universe, which he does once he realized the white noise machine manipulation and figured the only person who would do so was himself. Cisco then eventually realizes that Echo was using the Frame-Up and his arrest as a means to escape Earth-1 unnoticed. Thus, Cisco sets up a force field trap on Breacher and his fellow officers to give him enough time to stop Echo's escape while also giving the officers time to check the device that Cisco supposedly used to jot down his confession to the murder to instead explain how Echo tried to pull of his escape. Finally, Cisco knew that Echo would try to use the gun that killed to Gypsy on him if he brought it in his attempt to stop the escape. Thus, he reprogrammed the gun to instead trap the one trying to use it in a force field instead.
- Outliving One's Offspring: Poor Josh loses his daughter to Echo. He even has to directly witness her death.
- Out of Focus:
- Barry and Iris are on vacation for the bulk of the episode.
- Ramsey only appears in one scene.
- Papa Wolf: When Breacher thinks that Cisco was Gypsy's killer, he naturally acts angrily towards him. In fact, it's a sign of having come very far since we first met him that he is able to temper his urge to relieve Cisco of his head then and there because "breach psychosis" isn't his fault, and gives Cisco the chance to turn himself in.
- Pet the Dog: Ramsey spares Caitlin, due to their former friendship. He assures her it will be the only time.
- Poor Communication Kills: As Joe points out, Nash refusing to tell Team Flash what he’s looking for nearly gets the two of them killed.
- Redemption Rejection: Ramsey dismisses Caitlin's arguments of immortality being unnatural and then strangles her when she begs him to come back to the light.
- Red Herring: Zak Zeal, Cynthia's somewhat jerky ex-colleague is at first suspected of her murder, since he's the one who benefited most from it.
- Richard Nixon, the Used Car Salesman: Breacher initially refuses to believe that it was a doppelgänger of Cisco that killed Gypsy, considering that all the ones he knows of are pencil-pushes who lack Earth-1 Cisco’s scientific prowess.
- Shout-Out:
- Cisco's middle name is Baracus. And Ralph thinks he's "Hannibal" before Cisco calls him "Murdoch",quoting his classic "I love it when a plan comes together" line.
- Cisco mentions Wreck-It Ralph and Sweeney Todd.
- B.A.R.I. correctly identifies Barry’s favorite film as Jurassic Park, not The Empire Strikes Back as he first answered.
- Silly Rabbit, Cynicism Is for Losers!: Joe is confident that one of his friends will be able to rescue him and Nash from the cave-in, something Nash scoffs at, believing having faith in others is pointless. Joe is ultimately proven right when Ralph saves them just in time.
- Sliding Scale of Idealism Versus Cynicism: Nash is the cynic one, who mocks the idealistic one (Joe) for his faith in people and getting saved and is ultimately proven wrong.
- Taking You with Me: Before she dies, Gypsy makes sure Echo is trapped on Earth-1 and will be caught by Cisco. Qualifies as a Thanatos Gambit too.
- Third Line, Some Waiting: The A plot is about Cisco investigating Cynthia's murder, the B plot about Caitlin going after Ramsey and the C plot about Nash and Joe being trapped in the tunnels.
- Tomato in the Mirror: The vibes suggest that the murderer was Cisco, since he was sleepwalking and he had a lethal gun. Subverted, since it was an evil doppelganger called Echo.
- We Can Rule Together: Ramsey offers Caitlin this.
- Wham Line: Nash, at the end, reveals he knows how to save Barry.
- You Are Not Alone: Joe recounts to Nash the time just after he was separated from his wife; he felt utterly alone, and unable to cope with raising Iris by himself. Then he answered a knock at the door to find practically his entire neighborhood standing outside, offering him food and other methods of assistance.
