Final answer:
The irony of Tom pumping air for Ruby while diving might lie in the unexpected outcome or conflict between the act of ensuring safety and a deeper narrative twist. The irony reveals the gap between appearances and reality in the story.
Step-by-step explanation:
The irony in Tom pumping air through the hose while Ruby dives could potentially be understood in terms of the disconnect between what is expected to happen and what actually occurs. This passage seems to reflect a scenario where a character is engaged in an act that should promote life or safety—in this case, providing air to someone underwater—but the situation might be quite different, revealing underlying tensions or a deeper narrative twist. Without the specific context of the given lines (165–173), it's difficult to pinpoint the exact nature of the irony. However, if this scenario juxtaposes the responsibility of ensuring someone's safety with a conflicting interest or unintended outcome, that could be seen as ironic. Literary irony often plays off the readers' expectations and reveals a gap between appearances and reality, which seems to be implied here.