There are a few different reasons for a tortoise's continually trying to escape: The enclosure is too small, it's too hot/cold, it's too open, there are no hiding places and he doesn't feel safe. Any one of a number of different reasons. Take a look through our enclosure section and try to make your tortoise's enclosure a bit more comfortable for him. Try to make it 'feel' like he's really out in the wild, and not contained in a plain box. Give him something to do, something to walk around, something to inspect. If he's busy, he'll stop thinking about escape.