You could get a really big fuck off dog, a psycotic death machine. Leave it outside their door, cut their phone line. Im assuming they're tinks so they wont have mobiles so you should be safe. Now that they're in isolation, all you have to do is cut their water and eletricity off and wait. Its only a matter of time before they make a break out the door and as long as that honking big dog is there they stand no chance. Three days tops before they start getting desperit. Block off their stairs to so the postman dosent end up mauled too. Think about it, they'll meet their end at the hands of dehydration, aids or the jaws of the dog.