[Anyone else would get hung up on a subtle distinction between 'duty' and joy or pleasure, but not Nagisa. He knows what Rei meant and it's just as beautiful a sentiment as the hand-holding.]
You're good at it too.
[They keep walking and Nagisa starts to think more, but his smile doesn't fade.]
Action
You're good at it too.
[They keep walking and Nagisa starts to think more, but his smile doesn't fade.]
I'm really lucky to have you.