Answer:
The irony is that Ethan doesn't stay at home and leaves Mattie at the station.
Step-by-step explanation:
Ethan promotes situational irony when he disobeys Zeena's order. This is because it promotes a different result from that expected by both Zeena and the reader. His attitude in disobeying the order causes him to modify the story and promote something that no one was expecting, causing an unpredictable result that would not have happened if he had followed the order he was given.