Washing your rv in the lake

Not sure exactly how that happened. Owner initially says parking brake failed. Then blames the dog. Funny thing is, the reverse lights come on just before it starts rolling backwards. If the dog did do it, that's one smart dog to be able to release the parking brake, step on the regular brake and shift it into reverse. Also not very smart to keep it running when it's going under water. He obviously doesn't know/cares what happens when an engine ingests water.