The only thing that might make sense is if the situation was still deemed dangerous (there's an armed intruder who is not accounted for in this particular story and shouldn't be forgotten!) and they needed to get him clear of the situation because paramedics won't go in a hot scene like that.
Even with what appears to be lots of mistakes made, I really hate to see mistakes like this end up in lawsuits for what is inevitably, millions in taxpayer money. How millions of dollars fixes what happened to these people still needs to be explained to me before I'd award damages.
According to the other article linked somewhere on this thread, the man is still suffering from his injuries. I understand your concern about taxpayer dollars. (See my screenname.) But, the victim is entitled to some kind of restitution. Maybe police officers should carry insurance to cover potential victims in cases like this one....? Just a thought. Or do they already?
This case sounds terrible. The homeowner did everything he was supposed to do, and then LE messed up completely. Glad to hear he survived at least.