NOT safe in the backyard

I turned on the hose for him to water the garden. I set it at a low spray and stepped back in the house for a second. He turned the hose on full blast and aimed it at me. I barely got the door closed in time. After I documented the situation with both the camera and video camera, I began to worry about how I was going to get the water turned off.
He solved my problem for me. He sprayed himself in the face several times, became frustrated, dropped the hose and turned the faucet off all by himself.
That means he knows how to turn the hose on all by himself. Therefore, it is not safe in the backyard (if you want to stay dry).