When he's actively shooting, and word has it with a .50BMG, yes you take him down ASAP or suffer more casualties. And they countered lethal force with lethal force. Someoone's shooting at you. Just wait them out? Really??
So where do you personally draw that line?
Do the cops have to positively identify that the suspect is in the dwelling in question?
What other indiscriminate weapons should they be allowed to use?
Should the cops be able to just chuck a fragmentation hand grenade through a window?
If that's deemed "too dangerous", can they hit the building with an RPG?
How about mortar fire?
An airstrike? A drone strike?
Are they responsible for the financial liability of destroying a third parties property?
Are they responsible for other collateral property damage they cause?
Are they responsible for murder if they use indiscriminate weapons and kill an innocent?