I do too because I have too.
There may not necessarily have been a loud sound. The article talks about "small burn marks." It could have been a small popping sound muffled by fur. I think I remember reading that it only takes 50 milliamps of current to send the heart into ventricular fibrillation - that wouldn't make a loud sound. But probably if anyone had been there with a defibrillator, they could have saved both animals.