This happened to us once. There is a door on the TOP of our chinchilla cage. I had that open and we took the chins in the other room to play with them. I asked my fiance if he would put the chins away, but to make sure he remembere to close the door. He mush have had a brainfart or something because he thought I ment the regular door, and was a little confused as to why I would remind him to close that. He didn't even notice the top door was open.
In the middle of the night, one of the chins decided to run across the top of our desk which was next to the cage, and chew up all sorts of things. In the morning, he was back in his cage, but we had alot of ruined stuff!
We were glad that our chins were not hurt, but a little mad at ourselves over it. lol.
Silly chins.