I was a Vet Tech, And yes you do expect to get bit. In fact it is your job to make sure if the animal bites at all it bites you. In this case it does not sound like the Dog was actually being worked on. My guess is the tech was going to cut of the dogs identify collar or something and made a wrong move near a known skittish breed of dog. I have had to restrain a St. Bernard while surgery was preformed without anastesia. Yes it is dangerous, a dog will bite you when you inflict pain on it, you are also trained to prevent them from doing so but if you fail you are also trained to stuff your arm in the dogs mouth. In fact you hold the dog in such a way that one hand stops it from being able to bite and the other arm is positioned to be the nearest thing to bite. Vet Tech is a fancy word for chew toy....just kidding, but yes you accept the risk of being bitten when you take such a job. By the way I was nipped twice. Both times by Chihuahua's. they are terrified little guys and they bite.