You may fight – you may even start fights – but you may only use deadly force on a foe that is attempting to do you serious harm. Capture is not “serious harm” unless you are already under penalty of death or have a Code of Honor that would require suicide if captured. You never intentionally do anything that causes, or even threatens to cause, injury to the uninvolved – particularly if they are “ordinary folks.”
You only fight to defend yourself or those in your care, using only as much force as necessary (no pre-emptive strikes allowed!). You must do your best to discourage others from starting fights.