There is this video of a police dog in Spain that performed CPR on an officer who was down in action to revive him. The dog is named Poncho and it is not only proof that he was trained super well but also super neat to see what dogs can do through their instincts!
The video is from a training exercise where the officer pretends to be attacked and then the dog goes into action. Absolutely cool to see this! And I would definitely leave my life his this dog's paws!