Link's eyes widen, just a fraction. His arm! He'd seen how the man's arm moved - it was utterly natural, with no sign at all that the arm was mechanical.

He'll have to tell Zelda about this.

"Like a real arm!" he exclaims, as he leans forward, trying to get a closer look. And now that he is looking, he can see how it's not armour at all.

As he notes the fine joints in the metal arm's fingers, Link's own fingers absentmindedly wiggle.