The tittle Evans tries an O-level …

The term 'O-Level' in the play refers to the basic test in German taken by students in England, Wales and Northern Ireland. This examination is at the centre of Evans’ successful escape. It is in the guise of taking the O-level exam in German that Evans plans and executes his escape successfully. The holding of the O-level examination by the prison authorities gives Evans the chance to make a successful exit from the prison and it is also the question paper of this examination that helped the Governor track Evans at the Golden Lion from where Evans makes his final successful escape by fooling the Governor.
There is also a play on the term ‘O-Level’, which is short for ordinary level. It is a hint at the preparations that Evans had taken to make his escape successful. Though those were ordinary on the face of it, they helped Evans make a successful escape after four failed attempts earlier.