Yes accidents do happen..
my old vet killed my 5 year old yorkie.. so I know,,
but I tell you that once you know this.. you need to be changing your vets.. you should not hesitate..
It is very scary in my case the as little a file as my yorkie had he did not look to see how he did the year before after his needles and he had had a reaction.. gave him the same shot and it was fatal..
So this is only something for you to think about...
It is all pretty scary...