Fair enough. I'm willing to accept that palladium in the bloodstream might cause some nasty effects. But that still doesn't explain how the palladium got into contact with his bloodstream in the first place - the palladium core is shown as being at the centre of the arc reactor, which is never shown coming out of Tony's chest bloody. Even when Pepper removes the electromagnet itself (accidentally in IM1) it doesn't come away bloody (and, in another plot glitch, this electromagnet is never actually reinserted, either).