What a cutie Belle is. They can be quite the escape artists I tell ya. Looks like you'll need to add those locking clips to the crate.
When I was working in an office I had the VueZone cameras and just happened to check in on her. There's a crate on the left and she was in the X-pen on the right. Here's what I saw when I peek in.
All's good, both crates are there as is Emma.
Peeked in an hour later
She moved it 15 feet across the kitchen and over a runner rug and over the steps
And then she excaped out the bottom