Simon - an unrecognised genius or a total thicky..?

So I woke up at the unholy hour of 6.30 this morning (having gone to bed at about 3am- lovely) to find Simon wandering about on my pillow. Now being as I didn't feel like getting up right then, I thought I would leave him to motor about my room until I could be bothered to get up and catch him. I do mean motor; he does this curious snuffling thing as he explores and he's so fat that he can't really run, so he sounds like a depressed moped. Two minutes later, he was back at my pillow about to climb on my face so I had to get up and take him back to his tank. Now it might not seem like anything strange for a hamster to escape his box and go on a mission of exploration but Simon lives in a tank with very high sides and it's on the top of my computer desk, just below head height. Not only that but under the shelf is a load of junk including about 8 cardboard boxes, so I simply cannot understand how he made it out of his tank and down to the floor without killing himself. I also wonder whether he is completely thick and didn't know that he was wandering around in circles, or if he knew I would take him back to his tank and came to wake me up on purpose..