Yeah that's a literal different and I'd have to judge the threat to my physical being on the fly.
I'd liken this specific case with the 13 year old to someone breaking into my house and stealing something valuable and then me throwing shots as they're already running away. The physical threat is retreating by that point and I wouldn't feel comfortable murdering someone over material goods. Just my position.
If I'm in my car while someone is attempting to break in or I'm in my home and I'm aware someone is on the way in, the stakes are a little different and I'd have to play it by ear.
I don't carry gun thought FWIW, but I do think I'd be the responsible type if there's such thing.