If there was a firefight or if they were going to use explosives, they already had to clear the area, right? If you clear the area, there is no longer a concern to the lives of others.
Look at post #72 to see confirmation of my approach BY AN ACTUAL COMPETENT POLICE FORCE.
If I were one of the responding LEOs, and the guy was sniping at me or my buddies, I would want him taken care of ASAP, even if I had to blow up the shack. Combat ROE.