More stories like this one would be in the newspaper if guns were harder to get.
I expect the usual arguments imagining a victim shooting an attacker. But any, or even all, of these people might be dead if attacker or the adult victim had a gun; no guarantees regarding aim or ability of good guys and bad guys are available.
With more guns around, it would be safe to expect more problems like this one, a 2012 incident in which 9 bystanders were shot by the NYPD. And those are the well-trained professionals.