Somewhere along the line, he starts hissing through his teeth. It's meant to be a warning. He doesn't know this bot. He doesn't know what his intentions really are. If this is a BP model, then --

Then he's in danger. And Shadowmaru really did break his promise. A thought that hurts. It hurts enough to turn the hissing to a distressed whine, his teeth bared.

Why... why would his friend break that promise? Why would he let them capture him?

He's probably in danger and all Kagerou can do is think of why his only friend in the world would have let him down.