Junkrat gives a small sound of surprise-- he was evidently not expecting that kind of reaction. He yanks his tongue back in, trying to pull those fingers along with it, slamming his jaw shut; not hard enough to break a tooth on the Omnic's shell, but with enough force, he hopes, to make a point of his own.

He adds a sharp bark of sound on top, just in case his aggression isn't quite clear enough.