As far as Tony can tell, there are two potential meanings for Bruce’s question: what does he want to do with the paper he’s written the formula down on and what does he want to do with Extremis? The first question is far easier to answer, and much less controversial. Of course, if they cure Bruce’s radiation problem, if the Hulk disappears, then Tony won’t need to take the serum.

There won’t be a promise left to keep.

“I don’t know,” he says, looking back as guilelessly as possible and shrugging. Maybe he’s a coward just looking for the easy way out, but since it’s an option, he’s deliberately misunderstanding the question. “Burn it, I guess. There are some matches in the kitchen. We put it in a bowl, light it on fire, no one’ll be able to reconstruct the paper from ash. It’s the safest bet. And you won’t have to eat it.”