@Kathartes
No, regular security will just guard the target, like cossacks, who were tsar's "okhrana", but "okhranka" (or how it was officially called in short form "Okhrannoye Otdeleniye", lit. translation "Guard Department") was secrete service. They enlist provocateurs from parties, tried to prevent acts of terror, investigate the ones what happened and tried to catch known terrorists. Before the killing of Alexander the Second they were doing it quite poorly, were relatively efficient after that, and managed to be complete muppets around the time February Revolution and when Create October Revolution happened.
I guess it's either mistake of translators (more likely people from wiki, pretty much half of everything russia-related on wikipedia is wildly wrong), or manga author, as many things about russia is a bit off. (Like Bolsheviks and Lenin being a thing before 1917).