[ tadashi rolls his fist into a ball and hits hiro on his temple lightly. (not like he could ever be violent towards... well, anybody.) it's the same feeling when tadashi calls him a knucklehead and hits him on the head. ]

Don't get any ideas yet, [ ugh, definitely too late, and he can already tell. ]

It'll be better to let other people know that there might be a possibility. But all of these are just theories, anyway.