NYPD Gets Snuck On. Can happen with any situation even in a SHTF you wonder why people come back with PTSD and cannot sl

You simply can't turn your back into a open door when there's a gun owner in the house

They did not even clear the house at first. No tactics at all. -the Warrior

The officers covered each other. I don't think this was a matter of tactics . I simply think the only thing that would have helped is more officers on the scene , basically another unit outside covering them . Funny thing is now a days , you will see multiple , meaning upwards of 5 units , initially show up to a scene.
Then once it is deemed clear or safe by sergeant or senior patrol officer present, 3 of 5 units will depart.

This is why people looking on think a bomb went off , wondering why so many officers showed up, to something so simple. As you can see in that line of work , their is nothing such as simple ,easy , or obvious.