As applicable to countless other conflicts from any group of people in conflict with a standing army, people - insurgents/guerillas/franc-tireurs who can pick up a gun, fire and kill combatants and throw said gun down and become "innocent civilians"?
How can a standing army ensure a building which contains civilians and enemy combatants (willing to die for a cause) be sanitised with as few civilian casualties as possible, with maximum neutralisation of enemy personnel whilst keeping their own forces as safe and alive (as well as not mentally scarred)?