Mine very rarely comes out of the rockwork. I'm always checking the floor around my tank and inside the overflow box because I'm nervous. But then when I move a rock or two I see him scurry off..
Haha funny story, but one time I went to bring my filter sock down to the washing machine and when I turned it inside out, the mandarin plopped into the washing machine. Figuring he was dead, I scooped him out and held him in my hand while I went about my washing. Then when I went up stairs and tossed em in the toilet he jumped. Luckily the toilet was waste free and I grabbed him out and rushed to my tank. Since my overflow box is DIY, I didn't have it totally fish safe apparently and he went through about 5 ft of tubing/piping to get caught in the filter sock. Since then I've put a vent on the PVC leading down to my sump. But that was maybe 2 months ago and he's been okay ever since.