One trait I noticed about the form of Alex La Guma's novel is the size of many of the paragraphs. The paragraphs are quite big and dense. They are packed with thoughts from the characters, descriptions of other people, and various other sights and sounds from their environment.
The bulky paragraphs might conflict with the content since the characters themselves need to be nimble and alert. Unlike the overtly large paragraphs, Beukes and the members of the anti-apartheid group must be nimble, covert, and mobile. They try to be undetectable. When they are recognized, terrible things happen. When Elias is identified, he's brutally tortured.
Perhaps the supposed conflict between the form of the book and the content can be resolved by arguing that the myriad big paragraphs are needed to accurately convey the dilemma facing the activists. The form puts the reader in their position. Like Beukes, the reader must navigate an array of sights, sounds, thoughts, and dialogue all at once.