Ooooh, you made my heart hurt. How very sad. Yes, they are diggers and can get out of anything.
We had a team of construction workers here building a new out building for us several years ago. Nanuk would not leave them alone. He wanted to play with them. So, I chained him to a huge cast iron barbecue grill, thinking that would control him while I made a quick trip to town. Coming home, on my way up the gravel road to our house, I saw him, still chained to the grill......but 3/4 of a mile from where I left him. Never did that again.
Amazing animals. The best.
Sounds like my Mal...ROFL. I should have named him Houdini (escapes from anything).