While cleaning I removed a probe from one of the small slots in the lid. I didn’t notice that when I locked the lid to the enclosure it wasn’t positioned correctly and there was a tiny gap.
Last night I watched Mr Burrows go into a front corner of the tank, lean into the corner and lift himself straight up. He had seen the gap and was trying to push it open as a way of escape. He tried so hard but then fell over like a chopped-down tree. Fortunately the substrate is fresh and loose and he didn’t get hurt. But he quickly went into his shed. I made sure to properly lock the lid and then a while later observed the snake trying the same thing again, and once again he fell over. 😦