In a real zombie apocalypse, police colonels would take over the world

I saw the walking dead I know where this is going

Police don't have colonels.

In a real zombie apocalypse, no human would have permission to enter without permission of some other human, and most of these humans would not be willing to be part of anything like a government. In a real zombie apocalypse there would be a lot of dead bodies. If you're a cop or soldier, you don't want to be a part of that.

If you're a writer, you have to come up with what you think is the ideal situation. Maybe you write it down on the page, and it is your ideal situation, but you think, well, no one wants to be the zombie cop or the soldier in your story, the military. It's better for these situations, I think, to be imagined in a more realistic way. A lot of zombie stories go out of their way to leave these military characters like soldiers to do whatever they want, because it's just a different kind of soldier and for the most part, they're good soldiers.