What scares me the most is that here's a cop...a guy who is (in theory at least) trained to handle guns. Not only did he not realise the gun was loaded, but he was careless enough for it to go off in his hand (at least he was holding it towards the ground whenever his hand was near the trigger, as you're supposed to).
It's very easy to see how easy it is for a gun to accidentally kill someone

Wouldn't have one in the house...ever...