Possibly not but there is 'best practice' (albeit, ever evolving) and it's a fair assumption that any use of a firearm will result in an investigation, court case and possibly an inquest, during which a surprising amount of time is spent looking at matters such as training, capability, command decision making and intelligence available prior, during and subsequent to the event in question - I.e., not just the actions of the Cop during the immediacy of the moment. You know all of this.
No sane leaders of an organisation (in this case, senior police officers and Government Ministers) would expose themselves by pushing out a barely trained and non-competent individual to wreak havoc on the streets of Gotham City. The grief would be rolling in multiple directions.
Such an armed Cop is more than likely going to be a danger to themselves more than anything else.