Zombie Cliché Lookout:
Want to really put a relationship to the test? Give one person a deadly and extremely communicable disease. Before you know it, all bets are off as our natural instinct for self-preservation kicks in. In most zombie stories, the reaction to news of a zombie infection tells us a lot about the character. Those who are sympathetic and do everything to ensure the comfort of the infected tend to be either the heroes, or naive cannon fodder. Realists who want to distance the group from the wounded party come off as canny but heartless. And those who go completely nuts and try to murder their still-living friend in a state of utter panic are typically the story’s pathetic coward; you’ll want to watch out for this guy.
IMO, never have a loaded revolver around a panicky type. They’re more likely to pinch it and kill someone themselves rather than stay calm and rational.
And that’s a very powerful revolver too.
I don’t really know if I would characterise zombiism as an “extremely” communicable disease. Biting is a downright lousy transmission vector, especially for a species with teeth as crappy as ours.