12 Biggest Unanswered Marvel Movie Mysteries

In Iron Man, it is pretty firmly established that Dr Yinsen was forced to implant a dramatic electromagnet in Tony Stark's chest to stop the shards of shrapnel burrowing his way through his chest from killing him. In Iron Man 2, Stark himself upgrades the arc reactor that powers not only his suits but also that electro-magnet, which is still keeping him alive. At no stage is surgery considered a viable option, because it's too tricky, which is why it's easier to accept that Stark was allowing the reactor to kill him slightly while keeping him alive.

So how in Iron Man 3 does he suddenly get better? How is he able to have open heart surgery to have the shrapnel removed all of a sudden? If it's just a matter of a good surgeon suddenly appearing you have to wonder why Stark wasn't looking really hard for him when the arc reactor was literally poisoning him to death in Iron Man 2.

It's almost like it's a massive plot-hole that can't really be answered...