The idea behind having three tunnels was that if one of them was discovered, well, there would be another two, and the prison guards would hardly guess that the prisoners were working on more than one tunnel.
建造三条隧道的想法是, 如果其中一条被发现,还有另外两条, 监狱看守几乎猜不
囚犯在同时挖掘多条隧道。