I'm glad you got him back so quickly.
I remember once back when I was still living with my parents, I was out back by the pool and the neighbor kid just walked into the back yard. We had a privacy fence that opened on the side of the house. You can't see the pool from over there and he apparently had no idea I was back there. He was getting his ball that went over the fence, I told him to next time ring the doorbell and I'll get his ball. I remember worrying that that very thing would happen, he would let our dog out. Luckily our dog wasn't outside at that time.