People can say they know their dogs well, but in the end, there is no way to predict what a dog will do in unexpected scenarios. "Dogs will be dogs," is a cliché that actually rings true. Throw out a command to a dog when there is a distraction, and that command may very well be ignored depending on whether your dog has a better offer.
No dog is 100-percent trained, according to Clarissa Fallis in her article "An Off-Leash Walk Ended in Tragedy for My Dog, and I Was Powerless to Stop It." Fallis, a dog behaviorist and trainer, lost her own well-trained dog when he decided to run across a busy street because he heard another dog. This was a first for him, but it would also be his last.
She wrote, "I called out every recall word I had for him and even threw in his favorite word, 'cookie.' It didn't work. I watched in horror as a gasoline truck ran him over. In an instant, he was dead."