Unfortunately, that closeness of relationship has lessened over the years, although S.H.I.E.L.D. has still always honored its MCU roots more than any other Marvel TV series. That was certainly the case in the latest episode, which went all the way back to Coulson's "death".

Related: Unanswered Questions from Marvel’s Agents of S.H.I.E.L.D.’s Mid-Season 5 Finale

Kasius's End

In one crucial scene, Mack is being beaten down by Kasius. The Kree aristocrat has ingested a mysterious chemical to transform him into a ruthless, bloodthirsty warrior, and not even Mack can stand against him. Fortunately, S.H.I.E.L.D.'s tough guy gets help from Simmons; she shocks Kasius, using his own technology against him and giving Mack an opening. He grabs his shotgun-axe, twists the blade around, and stabs Kasius in the back with tremendous force. It's such a feat of strength that the blade emerges from Kasius's chest.

It's a stunning moment and a fantastic end for a villain who had become increasingly insane as the season continued. What's more, it demonstrates the strengths of the show's later timeslot; the entire battle was brutal and violent, while Kasius's death was suitably shocking. Surprisingly, though, there's more to this scene than meets the eye; it's a subtle callback to a key moment in 2012's The Avengers.

The Death of Phil Coulson

Specifically, this is the latest scene to evoke memories of the death of Phil Coulson. In The Avengers, Coulson shot Loki with a gun derived from Destroyer technology, only for the God of Mischief to teleport behind the agents and stab him in the back with his scepter. Quite clearly, Kasius's death mirrors this moment, present a more violent twist on the manner of killing; the camera angles deliberately invert this scene, an amusing - if subtle - shift.

Ironically, US viewers are less likely to spot that similarity than international fans. In the US, the MPAA viewed The Avengers scene as too gruesome for a PG-13 rating, cutting away at the point of insertion. International regulators were less concerned, so the film was shown unedited in countries like the UK.

Thankfully, Agents of S.H.I.E.L.D. has avoided Kevin Feige's "issues." The series now airs at a later timeslot, meaning the S.H.I.E.L.D. team have the opportunity to be a lot more violent and gory than Marvel's typical PG-13 fare. That makes the death of Kasius more than just an amusing callback - it's also a subtle piece of one-upmanship, a reminder that Marvel TV can actually do things that Marvel Studios can't.

MORE: Coulson’s Return For ‘Agents of S.H.I.E.L.D.’ Explained

Agents of S.H.I.E.L.D. will return on March 2 on ABC.