That's a stupid plan from the hero. If you give up the protection target to try and outmaneuver the enemy like that, what you will end up with is no protection target left at all. A simple counter to that is just to buy time and refocus on the soft target, that is to say, genocide the population. Literally nazi SS prison defense tactic here, but it works.
If they kill all the citizens there then there would just not be a city left at all, and even if the offices survive, they'd be useless without any citizen to serve. So wth even is that plan lol.