At the end of the Iron Lung movie, Simon does not survive; he dies when the submarine implodes while attacking the giant creature in the blood ocean, but he manages a small act of sacrifice that might help what’s left of humanity.

Quick Scoop: What Happens in the Final Act

  • Simon recovers the black box data from the earlier sub SM‑8, which may contain vital information about the mysterious “light” and the blood ocean.
  • Ava, the commander who has been directing him from above, admits she cannot rescue him but begs him to save the data, hinting it could help humanity’s survival.
  • Inside the sub, blood and fleshy, organic matter pour in, and Simon’s body begins to crack, blister, and partially mutate as reality slips and overlapping voices push conflicting agendas.
  • A second, eerie voice urges him to destroy the data so others never learn about the light, setting up a moral choice between protecting humanity or protecting the universe from knowledge of it.

The Ending: Simon’s Final Choice

  • Simon ties the black box to a life vest (or buoy) so it can float to the surface of the blood ocean instead of going down with him.
  • He sabotages the Iron Lung so its hull will fail under the extreme pressure, effectively turning the sub into a suicidal weapon.
  • He then rams toward the massive creature lurking in the depths; when it bites down on the sub, the weakened hull collapses, the submarine implodes, and both Simon and the creature are killed.
  • In the final image, the movie shows the life vest floating on the surface of the blood ocean with the black box intact and its beacon blinking, implying that someone (or something) can now find the data.

Does Simon Save Humanity?

Different viewers read this moment in different ways:

  • Bleak “tiny hope” view:
    Simon’s death buys a small chance that the surviving human factions can use the recovered data to understand the light, the creature, and the Quiet Rapture, maybe improving their odds of survival a bit.
  • Cosmic horror view:
    The universe in Iron Lung is indifferent; even with the data, humanity is fractured and nearly extinct, so his sacrifice may change nothing, reinforcing the idea that individuals are insignificant in a hostile cosmos.
  • Dangerous knowledge view:
    If the mysterious voice is right and the light is something that should not be known, then letting the black box be recovered might actually doom whoever finds it by spreading that knowledge further.

Themes Behind the Ending

The ending doubles down on the film’s core ideas:

  • Cosmic horror & insignificance: Simon dies alone, unseen, with no heroic send-off; the universe offers no explanation, only a brief flash of resistance before moving on.
  • Exploitation of convicts: He was always expendable “equipment,” sent in a barely suitable sub to an impossible mission, his death effectively an approved execution disguised as exploration.
  • Burden of knowledge: The fight over whether to preserve or destroy the data shows how dangerous information can be—both a potential salvation and a possible curse.

An easy way to think about it: the ending gives Simon no personal redemption or rescue, just a moment where he can decide whether his death means nothing or at least opens a narrow door for others.

Post‑Credits: Is There Anything After?

If you’re wondering whether to keep watching after the credits:

  • The film does not have a traditional mid‑ or post‑credit scene; there’s no extra teaser, sequel setup, or stinger after the main ending.
  • That clean break is intentional and fits the story’s tone: once the sub implodes and the vest surfaces, the narrative is over and the audience is left to sit with the dread and ambiguity.

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