This is dumb, wondering how we failed as a society that a 17 year old kid ended up with a gun trying to rob somebody and ended up shooting them and himself, is not a bad thing to try and assess.
Also as another thing to mention, not victim blaming, obviously person committing crime caused bad thing to happen, but when someone threatens you with a gun or knife for your money or watch/jewelry, just give them your *****. Getting shot or stabbed is not worth your stuff, you should not go after the weapon unless you really think they're going to use it anyway.