“Whose home is a place/ he might, this time, never get back to?” - rhetorical question, parenthesis, enjambment.
Parenthesis of “this time” makes the phrase stand out and reminds the reader again how much danger the cop is in as he goes about his job. He could easily be hurt or killed.
Rhetorical question forces the reader to stop and think about the nature of the cop’s job and consider the dangers he faces on a daily basis. MacCaig wants us to feel sympathy for the cop by making us think deeply about his work.