My dog Sydney
HATES the vet , and we have a
wonderful vet who has never done anything to her to make her dislike her so much ( except give her her shots...which I am guessing , Sydney remembers very well
)
Sydney will bark and growl ( alot) but the vet handles her very well . She is firm but has never tapped/smacked her nose or given a correction like that , she holds her a certain way ( which I can't duplicate ) and lets her know she is in charge and not there to hurt her , and Syd will eventually calm down. I think some dogs are more fearful than others and since it was his first time acting like this I feel he was more scared than agressive. BUT I agree if he continues to act this way in other situations , you need to put a stop to it.
I can't say if I would leave over it , But if you feel uncomfortable than go with your gut.