More cores from that particular rifle ammo will blow through an attacker and hit bystanders. A pistol is far better for use inside a building. That still stands, if the attacker is wearing body armor (first hitting round buys at least a fraction of a second).
Those rifles are pretty fashion accessories, though. So tacticool.
Thanks for the additional comment.
The whole things sucks, from years earlier until after the event. What a mess.
All this, because agency after agency after agency after agency after agency after agency and others too, simply refused to do what should have been a bells and whistles no-brainer.