In Iron Man, Tony Stark uses a minified version of the Arc Reactor in his chest to keep shrapnel out of his heart and other organs.

When the Arc Reactor is removed (for changing palladium, stolen by Obadiah Stane, damaged, etc) Tony starts agonizing, but why he didn't die immediately?

I think the blood would carry the shrapnel in a really high speed so Tony would have his organs damaged almost immediately, and even after replacing the Arc Reactor, it would be too late and his organs were already damaged.

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    From my understanding the metal fragments were not in his veins or arteries, but embedded in the muscles of his heart itself. The danger was that the rhythmic beating of his heart muscles around the fragments would cause them to dig into more heart tissue and migrate to his bloodstream. The magnet wasn't to pull them out completely, but rather to keep them from working their way deeper into his heart muscles and doing more damage. When the electromagnet is turned off, they start digging into fresh muscle causing pain. Commented Sep 22, 2014 at 4:42
  • @JohnMeacham In this case this could happen, resulting in more damage: sketchtoy.com/63101269 Commented Sep 22, 2014 at 4:52
  • Are you asking in-universe or out-of-universe?
    – Möoz
    Commented Sep 22, 2014 at 5:11
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    @TiagoMarinho I believe the fragments would all be on the side where the blast came from, since if they penetrated to the other side he would have died from the initial blast tearing up his heart. You can see from the clip youtube.com/watch?v=Xgyc2Mgqs6Q (2:20 mark) that he takes the blast directly to the front of his chest so a magnet in the front would be in the right spot. Commented Sep 22, 2014 at 7:59
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    @TiagoMarinho An "out-of-universe" (real world) explanation of something might include the writers making a mistake or wanting to write a good story at the expense of realism. An "in-universe" (fictional world) explanation of something could only involve the fictional events and physics of that fictional world. For example, in Star Trek the in-universe explanation of why advanced races are so similar is that an ancient race seeded life across the galaxy. The out-of-universe explanation is that it makes the show cheaper to produce and easier to understand and watch.
    – Tim S.
    Commented Sep 22, 2014 at 16:28

3 Answers 3


In short: the shrapnel kills over a period of time and not immediately.

  1. The shrapnel fragments were not immediately fatal. They simply moved closer to his heart and vital organs gradually. As Yinsen says in Iron Man, they called such people "the walking dead" because they would slowly die over a span of months.
  2. The electromagnet stopped them progressing from the moment he first inserted it. Thus, it would take them that much longer to actually become life threatening.
  3. Except for the Obadiah Stane part, the arc reactor was removed for a minute or two at the max. That was certainly not enough for the shrapnel to suddenly jump to his vital organs.
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    Nice quote from Yinsen. I was missing that. Commented Sep 22, 2014 at 5:08
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    Further evidence to back up this claim -- if the movie shrapnel would kill Tony immediately on the removal of the reactor, he could not have been saved after the original attack where he got the shrapnel in the first place, (since surely it took a lot of time to get him to Yinsen, and for Yinsen to operate and rig up the electro-magnet.) and most of the Iron Man movie would never have taken place.
    – Kai
    Commented Sep 22, 2014 at 17:32
  • @Kai - yes... correct. I focused on this part because the OP asked about removal of the arc reactor.
    – Stark07
    Commented Sep 23, 2014 at 2:33
  • So Rick, Michone et al are just figthing some random dudes with shrapnels in their bodies ? This is getting confusing...
    – Kalissar
    Commented Apr 7, 2016 at 10:57
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    I know. And I remember this scene of the first Iron Man well. I was just trying to a joke :-(
    – Kalissar
    Commented Apr 7, 2016 at 11:28

AFAIK in the scene with Stane, the agony was caused by the neuro-blocker (or whatever) that also made Tony's ears bleed. In the scene where Tony asks Pepper to help him replace the reactor, he is clearly not agonising more than Pepper does :)

So in my mind Tony could indeed survive for a few months without an ARC Reactor, being a "walking dead" during that time, in the definition given by Yinsen.


The arc reactor slowed the shrapnel down long enough to stop it from killing Tony when Obadiah pulled the arc reactor out of him, Tony would have still had plenty of time to put in a new one in since if the shrapnel was shot directly into his heart he would of died instantly but it was just dangerously close.

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