The obvious show of reassurance helps a lot. They've met other people with that particular reaction, just most of them didn't have floating computers that zoomed right up in Soldat's face without warning like that. That they're still jumpy from the fireworks doesn't help, either.

Soldat bows their head a moment, thinks of folding origami for a couple breaths to calm down, then uncurls their arm from their chest and pulls up the sleeve to show him. The metal definitely goes further up, at least to the elbow-- what little scanning the computer got in might even show how it goes all the way up to their shoulder. "Here. I can pop a plate open for you. And explain what I know about it."