This article contains SPOILERS for Pluribus Episode 4.
Pluribus season 1, Episode 4, "Please, Carol," shows Rhea Seehorn's title character injecting herself with something that has a strange effect, but it's just one step in what is an incredibly risky plan. Most of "Please, Carol" deals with the immediate fallout of the previous episode, which saw Zoisa (Karolina Wydra) saving Carol's life from a live grenade. However, there's a moment from Episode 3 that is made way more important by Episode 4's efforts, as it gives Carol an interesting idea.
Seehorn's character has made no secret of the fact that she wants to reverse the Joining that has swept the world into one big collective consciousness, even telling the Others themselves that this is what she wants to do before it's too late and she becomes like them. Showrunner Vince Gilligan has given Carol very little to work with, though, which has made Pluribus very frustrating so far, but in the best kind of way. In "Please, Carol," a small vial and hypodermic needle get her surprisingly far before things go wrong again.
Carol injects herself with thiopental sodium in Pluribus Episode 4
After offering Zosia a drink in the previous episode, Carol discovers that an individual Other becoming intoxicated doesn't impact the entire Joining. Instead, it's limited only to the body that consumes the alcohol. When Carol also figures out — via Zosia's refusal to answer the question — that there is a way to reverse the Joining in episode 4, Seehorn's character combines those two precious pieces of intel.
Liberating a vial of thiopental sodium and using a textbook to figure out a non-lethal dosage, Carol injects herself with the drug and sets up a video camera to record herself. What Carol is doing here is figuring out if what she's read about the drug is true. She needs to know if it acts as a sort of truth serum by lowering her inhibitions, making her admit things she wouldn't usually say out loud, and then forget what she said. Carol ultimately discovers that that is indeed what the drug does to her, and certain medical sources confirm that this is generally accurate to real-life science.
Why Carol then injects Zosia with thiopental sodium
"Please, Carol" shows Seehorn's character figuring out that the Joining cannot physically lie to her, but information can be withheld by the Others. The only thing Carol wants to know, which Zosia isn't telling her, is how the Joining can be reversed. Because Zosia's body is still recovering from the grenade blast at the end of episode 3, Carol uses that to her advantage and spikes Zosia's IV with the drug she took from the hospital pharmacy, now more confident that it will work on Zosia after the trial run.
When it kicks in outside, it's clear that Zosia is fighting especially hard not to share the information that Carol is demanding from her. The thing is, Zosia's connection to the Joining doesn't appear to be severed, and so she is able to summon nearby Others to try and dissuade Carol from what she's doing. Having miscalculated the dosage, Zosia's collapse means the remaining Others, who are in full control of their faculties, are immune to Carol's specific line of questioning, and they're also too busy trying to resuscitate Zosia after she slips into cardiac arrest.
The fact that Carol opts to try the drug on herself first further proves something she has clearly been trying to bury. She cares for Zosia, regardless of whether she perceives Wydra's character to be an individual or a part of the Joining. If she didn't, she wouldn't have had any problem risking Zosia's life the way she did. Furthermore, Carol is visibly shaken when Zosia collapses, cementing the fact that Zosia is far more than a conduit to the Joining or a guinea pig to Carol.
Carol's latest failed attempt to "fix" the world sets up a great run of Pluribus episodes
Carol is not equipped to liberate humanity from the oppressive contentment that the Joining has brought them, but it hasn't stopped her from trying. That said, everything she has attempted so far has not gone according to plan. Her plan to bring the unjoined individuals together achieved very little, and anytime she gets too openly upset with the Others, droves of them die due to their inability to process volatile emotions.
Carol's plan with the thiopental sodium was her most inspired scheme yet, but even that went wrong, and now it's very unclear what her next idea will be. With five episodes left to go in Pluribus season 1, there's still a long way to go before the Apple TV show can reach a suitable stopping point, so all we can do is theorize about what Carol's next steps will entail.
Pluribus is streaming now on Apple TV, every Friday until the season 1 finale on December 26, 2025.