Nothing after the fact. I would try to find out what the circumstances were when he bit them? What were they doing? How many people were dealing with him at the time? Was a new person attending to him? Did they nip a nail or was he in any other way hurt or scared? Huckleberry hates going to the vet and, other than this last time, has needed to be muzzled as he will bite. But he is terrified and that's the reason for his aggression. If it were me, at least the next few times he needs to go then I'd be there with him if at all possible. Information is key. Who, what, when, where, why....good luck.