"Built like a gorilla but less timid, / thick-fleshes, steak-coloured"
Simile - the poem begins with a cliched simile, a stereotype: the cop is compared to a gorilla, which signifies his enormous size and brutal strength, through the phase 'but less timid' reinvigorates the cliche, as it humorously suggests that the cop is even more vicious.
Compound adjectives - the compound adjectives 'thick-fleshed' and 'steak-coloured' are metaphors portraying the cop's face as animal-like and tough; his features are dark - both physically and emotionally.
"hieroglyphs in his face that mean / trouble"
Symbol - a hieroglyph is a form of writing associated with Ancient Egypt, consisting of representative pictures that aren't always easy to read. Here, MacCaig is using it as a symbol that can be 'read' as facial disfigurement and, at the same time, a sign that he can be 'trouble'
Enjambment - forces the word 'trouble' onto the beginning of the next line, thereby highlighting it.
"he walks the sidewalk and the / thin tissue over violence"
Metaphor - the metaphor 'tissue' creates a contrast between the tough cop and delicacy of tissue; 'he walks the sidewalk' is physical and hard, while in the next line 'thin tissue over violence' is metaphorical, suggesting that a civilised society (represented by the 'sidewalk') can so easily tear apart (represented by 'tissue) and descend into violence.
""seeyou, babe""
Word choice - of "babe" has connotations of tenderness and affection. This is effective because it shows the love that the Brooklyn cop has for his family, contrasting with his tough and violent job. MacCaig uses language here to humanise the Brooklyn cop and show him as a man with loved ones, just like the rest of us.
The stereotypical "see you, babe", devoid really of any emotional meaning - it's routine, expressionless.
"he hoped it, he truly hoped it."
Repetition - makes clear his underlying vulnerability that he hides from his wife.
"He is a gorilla"
Metaphor - highlighted by being in a line itself - the metaphor makes the comparison more certain, hardening the brutal, tough, heartless image of the cop - at home he is vulnerable, but outside he appears hard and invincible.
Repetition - of "should" reveal the deadly street violence he faces.
Alliteration - of the 't' sound in "tissue tear" and the kinetic images (images involving movement) of 'tear' and 'plunge', all combine to create the idea of destruction, resulting in falling uncontrollably from a great height.
Enjambment - isolates 'into violence' onto the next line, thereby highlighting it
"Phoebe's Whamburger"
Onomatopoeia - of 'whamburger' makes the place sound so perilously violent
"gorilla with a nightstick"
Extended metaphor - gorilla is mentioned 3 times, it is now almost used as the cop's name, he's embodied the violent animal, everyone see's the police as bad and threatening as many people want to do illegal and violent things, criminals see him in the worst light
"this time"
Parenthetical - 'this time' is inserted to further our sympathy as we understand that he might not make it back to the safety of home.
Penultimate verse, it's structured as a rhetorical question. The question engages our sympathy for the cop - we would not want to be him.
"And who would be who have to be his victims?"
Last sentence begins with an 'And', the effect of which is to isolate and highlight the last point about to be made. It is also another rhetorical question, but structured in a way which causes a double-take.
The criminals are seen as 'his victims', causing the reader to pause to absorb the point. The clause 'who have to be his victims' is the complement of the verb 'would be' (the verb 'to be' takes a complement, agreeing in number and case with the subject) - and then we realise that the cop can be as violent as the criminals. He becomes a symbol for so many people, capable of both good and evil. Despite being a protector of law and order, he is capable to being evil.
Themes
The poem presents a convincing character, and deals with isolation, fear, suffering, violence, human nature, good and evil.