I would expect they probably brought in outside contractors to do the work. It's somewhat specialized work, and there probably aren't enough locals with the skills. That said, sounds like a decent zombie apocalypse refuge. But seriously, if you know that clearing the are is going to ruffle feathers, clear more than you need in the first shot to leave you room to expand later without having to get permission to clear more. Because now people will be watching. It's a business, not a person. Morals don't exist. Which is why decision makers at businesses should not be shielded from prosecution and jail time.