Teresa was struggling with what she should eat for lunch. What literary term is this

Cameron, who has an extreme and unreasonable suspicion of other people and their motives, suffers from paranoia which is a psychological disorder characterized by delusions of persecution or grandeur, was absolutely sure that someone was following him even though he was absolutely alone and hadn't seen a car for miles and miles.

How does this comparison reinforce what powell is trying to say in this paragraph

The waves crash on the shore ? alliteration ,assonance,onomatopoeia