Irony of justice
Clark admits during the play that he is a pedophile. However, he is ironically set to be freed at the end of the text due to a lack of evidence.
Dramatic irony
The court decides to release Clark due to a lack of evidence. However, as an audience, we see a conversation between Clark and Juan in which he admits to being a pedophile. As such, there is a sense of dramatic irony, as we know something some of the characters are not aware of.
The day of his release
The day of Clark's release, he is killed by the other inmates. This is ironic as if he would have left a day earlier he might have survived.
The most peaceful block
Mr. Nett brags that his block is among the most peaceful in the prison, with few violent incidents. Ironically, ust after this Clark arrives, who is soon after brutally murdered by the other inmates.
Irony of prison
In this play, Pinero shows that the dynamics and relationships in prison ironically reflect the outer society. As such, he emphasizes the fact that prison mirrors the outside world in many ways, offering an insight into human nature and power dynamics.