Yes, firing a gun in a crowded subway station is absolutely in the wrong, as we can see by the three innocent people shot, one in the head. There are police forces across the world trained to deal with assailants with deadly weapons including knives without shooting them. It’s reasonable to expect the NYPD to have the same level of training and judgement.
Sounds more like TF2 crossed with DOTA, which sounds weirdly fun and hella toxic.