orangebird used to do that - once he was stopped by hotel staff as he was about to walk out of reception onto a busy junction. They seem to grow out of it fairly quickly, though - hang in there! Meanwhile, you might find it helpful to put a stairgate across her door - with luck, she won't be able to undo it in her sleep and will eventually learn to wake up at that point and go back to bed. Most of orangebird's episodes didn't require any adult intervention, once we all adjusted.