Answer:
The purpose of the last line was to emphasise & buttress the feeling of frustration felt by everyone
Step-by-step explanation:
Going with the notion that the last line of the chapter on page 66 is "and every face I saw looked ready to kill somebody.". Following through the context of the narrative, we see that the current situation was that the air-conditioning system of the Logan airport was faulty. This caused a great inconvenience for the people which was made evident by the fact that they were all sweating. The writer thus uses the last line to further buttress the unease and inconvenience which was felt by everyone.