"Yup, that way in case it happens to one of us he'll know too." Just sharing information, that's it, nothing more. That's all, Yamamoto is being honest, even if he is holding back part of his reason.

He will also keep an eye on his friend, make sure the other boy doesn't suddenly start acting like a dog again or get himself hurt in some way from it. After all, when he started barking it was like the bomber went off his game completely, he was acting like a dog.