50-year-old Choi Gap-Bok had spent a life in and out of prison when he was jailed on suspicion of burglary, but the yoga master had basically been training for this eventuality for years without even realising it. In 2012, he was allowed to be given a special 'skin ointment' from the guards, and once the three officers on duty were all sleeping, he applied it to his upper body and incredibly squeezed himself through the food slot where his meals would arrive. He passed through the tiny 15cm x 45cm gap in just 34 seconds, before slipping away. He was caught six days later and thrown into a cell with an 11cm slot... Challenge accepted?