The Centipede Serum Choice Is A Red Herring
Season 5 has seen Agents of S.H.I.E.L.D. toy with the audiences' expectations like never before. The second half of the season, for example, carefully set up a number of potential "Destroyer of Worlds," before settling on General Talbot, a character nobody had considered. With attention focused on the options of Quake or Ruby, nobody noticed that Talbot had grown a beard similar to the comic book version of Graviton, and begun dressing in blue. The signs were all there, but the series was distracting its viewers with a false choice. The trailer for "The Force of Gravity" focused on the idea that the prophecy is true, and featured dialogue where Daisy calls herself "the Destroyer of Worlds." It made viewers believe Daisy had acknowledged herself as that dangerous being, when in context she simply said it to muster up the strength of will to resist a Kree device. This half-season has all been about misdirection.
The Centipede Serum choice is another misdirection, albeit a very sophisticated one. It seems the Serum works in a similar way to the particle infusion process explored earlier in the season, allowing another substance to be bonded to a being's cells and granting them the properties of that substance. Thus, the Centipede Serum can be used to bind Jiaying's healing properties to Phil Coulson, but alternatively, it could be used to bind the Confederacy's Odium toxin to Graviton, killing him. S.H.I.E.L.D. only have the one sample, and must choose how to use it.
But here's the catch: using the Centipede Serum to bind the Odium to Graviton in order to kill him would be a terrible mistake. While the Odium is fatal, that isn't why the Confederacy use it. They use it to give themselves what Kasius called "a fearsome last stand. A brilliant flash of light and splendor." A being who has taken the Odium sees their every ability enhanced for the last few minutes of their lives, and their inhibitions are drowned in a furious bloodlust. Now imagine Graviton under the influence of the Odium. Yes, Talbot would ultimately die, but for a few brief minutes his powers would be greater than ever before, and he'd have absolutely no self-control. If anything could crack the planet like an egg, it's Graviton dying after the Odium was introduced to his body.
Save Coulson, Save The World
The central theme of Agents of S.H.I.E.L.D. is not "science trumps all." Rather, it's "family." The showrunners are well aware of this fact; in an interview with Comic Book discussing Season 4, Jeph Loeb explained that was why they used Robbie Reyes's Ghost Rider rather than Johnny Blaze's. "Our show, at the end of day, is always about family," he explained. For the conclusion of Season 5 to be satisfying, it doesn't just have to be dramatic and epic; rather, it has to fulfill the show's themes. It has to be about "family."
Over the last five years, Coulson hasn't just forged a team - he's built a family, one that stands at the center of Agents of S.H.I.E.L.D., motivated by their love for one another. Like any family, it's sometimes a bit dysfunctional (the scrap between Daisy and Yo-Yo in "The One Who Will Save Us All" is basically two sisters having a fight). But S.H.I.E.L.D. is still a family, and the bonds of love are strong between the team's various members. "The Force of Gravity" went to great lengths to remind viewers that Talbot is a part of that family. Coulson loves Talbot like a brother, and - underneath all the insanity and psychosis - Talbot loves Coulson too. Even after six months in a Hydra prison, Talbot held on to the hope that Coulson would come to him.
The solution to S.H.I.E.L.D.'s Graviton problem is not pseudo-science, it's the faith and love that Phil Coulson offers unreservedly to those who are part of his family. S.H.I.E.L.D. don't need to kill Talbot, they need to talk him down. And there's only one man who can do that: Phil Coulson.
Agents of S.H.I.E.L.D. season 5 concludes Friday, May 18 with 'The End' at 9pm on ABC.