That Breaking Bad Moment In Agents Of S.H.I.E.L.D. Was Completely Improvised
"Agents of S.H.I.E.L.D." was a changed show in its second season. In its early days, the Marvel Television series suffered from an identity crisis. Season 1 started out trying to emulate co-creator Joss Whedon's previous work, yet it played as a pale imitation of shows like "Buffy the Vampire Slayer" and especially "Firefly," following a ragtag team of misfits on weekly adventures in their flying home base (in the case of "Agents of S.H.I.E.L.D.," the heroes' beloved Boeing C-17 Globemaster III or "The Bus," may its memory be a blessing). However, the one-two combo punch of Whedon stepping away from the series and "Captain America: The Winter Soldier" blowing up the Marvel Cinematic Universe's status quo near the end of season 1 proved to be just the creative boost the show needed.
Upon returning for season 2, "Agents of S.H.I.E.L.D." had gained a newfound confidence. Its characters began to take on greater dimensions, it really embraced the idea of being a show about everyday people trying to keep the world safe, and it even started delving into the weirder and wilder corners of Marvel comic book lore that the larger MCU has continued to ignore to this day. Season 2 also introduced Inhumans into the equation and came closer to presenting them as a viable replacement for the X-Men than any other project from the House of Ideas at that time. (Marvel's attempts to supplant the X-Men with Inhumans back when Fox held the "X-Men" movie rights is a saga unto itself.)
That sense of surety extended to the series' cast, who grew increasingly comfortable in their roles and willing to ad-lib as they saw fit. So it was that Iain De Caestecker was inspired to salute a fellow small-screen science bro as Leopold "Leo" Fitz in the season 2 finale, "S.O.S. Part 2."
Iain De Caestecker channeled his inner Jesse Pinkman for Agents of S.H.I.E.L.D.
Fitz, who started out as one of two science whizzes who provided the do-gooders in "Agents of S.H.I.E.L.D." with their nifty gadgets in season 1, was in a tough spot when season 2 began. Having almost died after professing his feelings for his partner in science crime (er, figurative crime, that is), Jemma Simmons (Elizabeth Henstridge), and saving her life at the end of season 1, Fitz was still firmly in recovery mode when the second season picked up. The show didn't fast-forward through Fitz's healing process or skip right into the next phase of his and Simmons' slow-burn romance either, which made it all the more satisfying when Fitz was finally back on his feet and ready to move forward by the time "S.O.S. Part 2" rolled around.
No moment signified this more than when Fitz and his fellow S.H.I.E.L.D. agents, specifically his big brother-y buddy Alphonso "Mack" Mackenzie (Henry Simmons), and boss Phil Coulson (Clark Gregg), successfully laid a trap for their enemy Gordon (Jamie Harris) — an eyeless teleporting Inhuman whose makeup was probably only slightly more comfortable than Alan Cumming's getup as fellow teleporter Nightcrawler in "X2: X-Men United" — using the power of Science™. Reveling in his triumph, Fitz informs a gobsmacked Gordon that he has, in fact, been cornered through the magic of "Science, biatch," doing his best to channel Aaron Paul's Jesse Pinkman and his iconic catchphrase from "Breaking Bad." That Fitz doesn't quite pull it off is certainly on-brand for the S.H.I.E.L.D. team's resident lovable dork.
Clark confirmed this moment was completely improvised shortly after "S.O.S. Part 2" aired. Meanwhile, the episode itself affirmed that "Agents of S.H.I.E.L.D.," much like Fitz, was stronger and better than ever before.