It's May vs. the Patriot in “No Regrets,” the next episode of “Marvel’s Agents of S.H.I.E.L.D,” and it seems as though the ace pilot has access to a little super-serum that could shift the odds in her favor.

While it's fun to watch May open a righteous vial of whup-ass, the real tension of the episode surrounds Agent Fitz and his newfound willingness to kill in cold blood. As the promo's captions put it, "Heroes are terrorists. Trust is weakness. What is real?" In the virtual world of the Framework, where Hydra rules, it is getting increasingly difficult to know quite where each one of our heroes' loyalties lie.

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According to the episode synopsis, "The truth behind Fitz’s turn could bring down all of S.H.I.E.L.D.," which raises the question: Which S.H.I.E.L.D.? The one in The Framework, or the one in the real world? Either way, it could be bad news for at least some of our characters, especially those who -- like the unreliable scientist Holden Radcliffe -- can now only exist in the virtual world, as they lack a real-world body.

Airing Tuesdays at 10 pm ET/PT on ABC, “Marvel’s Agents of S.H.I.E.L.D” stars Clark Gregg as Agent Phil Coulson, Chloe Bennet as Daisy “Quake” Johnson, Ming-Na Wen as Melinda May, Iain De Caestecker as Leo Fitz, Elizabeth Henstridge as Jemma Simmons and Henry Simmons as Alphonso “Mack” Mackenzie.