Throughout the series, Mac has shown that he will protect three things at any cost: The honor of his country (through his military service), the safety of his city (through his work at CSI), and the integrity of his lab (by suspending or firing workers who fail to abide by the rules). Strict but fair with his colleagues, his "follow the book" approach, perhaps due to his military background, has sometimes put him in conflict with those working under him, as shown in instances where he was forced to take disciplinary actions against Danny, Sheldon, Stella and Adam for going against protocol, but also trusts his team and has repeatedly defended them from unfair criticism by the bureaucracy.