What makes lines 12-13 an example of situational irony

Incomplete question. I provided an explanation about irony in literature.

Explanation:

Situational Irony is a literary device used by an author to express an action in the plot of a story that is totally different from what the reader would expect.

For example, a protagonist (the leading character) in a story with so much life in one story unexpectedly and tragically died. This is ironic because the reader would naturally expect the protagonist to save the day.

b. our party quickly made its way into the cave / but we failed to find our host [the cyclops] himself inside.