“Better than nothing, but just imagine what he could have accomplished with an M14, or even a shotgun.”
In close quarters, such as in a house, with doors and hallways and several bad guys wanting to get to you and your family, an M14 would be more of a liability than an asset. A short-barreled shotgun would be better, but still not optimal. A Glock 19 would be a better platform under those circumstances (15 rounds in the mag and 1 in the pipe; and a quick magazine change); though being a good shot is critical.
There were plenty of targets outside of the house at the start of the engagement.
Pistols are fine, but it surely would have been nice to be able to reach out and touch somebody while they were 50 yards away in the street.