Endless detention ... the mother of Atputha, 7, and Abinayan Rahavan, 4, is considered a security risk by ASIO. Legitimate refugees, including toddlers, are imprisoned indefinitely. Only ASIO knows why and it will tell no one, writes Kirsty Needham. 'I live like a dead man walking,'' says Suvenran Kathirdamathambi, or ''Sutha'', 32. ''This is supposed to be the golden period in anyone's life - your 20s and 30s. But I can't even say when the day starts.'' Sutha is married, but his wife lives alone in Sri Lanka, unable to tell anyone she has a husband who has spent 30 months locked up in Australia. The former paramedic sleeps in short spurts, sharing a room at Villawood detention centre with men who sporadically wake at different times, miss breakfast, smoke heavily, shun exercise and mope around under trees. ''No one is in their right mindset,'' he says by telephone. ''To pass one day is a