[Leo gets the hint and moves away a little. He nods as Tony explains that he didn't make the initial design, but his father did. And then he mention the shrapnel. At first he wonders how he got close enough to have
shrapnel
close to his heart, but then he thinks that he was right, and they weren't so different after all.]
So it keeps you alive.
[He doesn't say it in a way that might imply that he would take advantage of it. In a way, his tone is... understanding. Tony needs that to live, just like Leo needs the part of his brain that's synthetic.]