Having been a military servicemember, not returning fire is the bare minimum to expect. If they had no training, no mandate, no authority, and were not kicking someone's door down in the middle of the night, then returning fire would be a risky but understandable choice. But if you have any understanding of tactical urban combat, you know that taking cover here and assessing the situation is the only rational choice. Blindly returning fire in an area filled with civilians (an apartment for god's sake) is a criminal decision, likely to get your officers and random innocent persons killed.