I don't have any advice for you, but here's a good true story.
I have 2 Chihuahuas and a few years ago I adopted another rescue Chihuahua who was two years old. It was sort of a spur of the moment thing, and after the dog was brought over to me and we all got acquainted I had to get a new collar for him. The one he had on was way too tight, and choking him. So I removed his collar and went out to Walmart.
I don't drive, so I had to take the bus. I was gone for about two hours. When I came home, and was walking on the sidewalk to my house, about six houses away, I see a dog standing on the sidewalk in front of my house. It looks like Chi Chi, the dog I adopted. But, I thought it must be a stray, can't be my new dog.
The closer I got, the more I realized it WAS Chi Chi. OMG, how did he get out. I had locked the door good when I left the house... no way for him to get out.
I called his name and he came running towards me.
Turns out, he had a project going on, after I left the house. He dug an opening large enough for him to escape from the back yard. It was where the wood gate is between the cement wall. The ground cover there, as it is in my whole back yard, is pea gravel. This dog, who I had owned for about an hour before I left the house, dug his way out of his new home and waited for me to come home. I was amazed to say the least. He had not wandered away, just stayed in front of my house on the sidewalk waiting patiently for my arrival. I was horrified at what could have happened... hit by a car, lost, whatever!
My neighbor came over and nailed a platform of wood across the ground so that would never happen again.