He took the master key and pressed it into melted candle wax, making a perfect impression. The mold was smuggled out of the prison, and his allies used it to make a metal copy. They hid it inside a cake and sent it back to him.
But when he tried the key, it didn't fit. So, he sent another wax impression and waited for the cake. And this time, the key worked.
He passed through every locked gate, simply walking out of the prison. And years later he became president of Ireland.