Though I can understand Saburou's frustration at being given a hard line of denial in his hopes of returning home, his move to strike Atomos, if that's what he was going to do, was highly uncharacteristic; and especially given that he felt a strong kinship with the lad. That whole scene felt very forced, and conveniently served to reinforce the label spat at him by the individual who stole Atom away at that moment.