This is how my father taught me to split green, frozen wood up to maybe 10 inch diameter logs.
Oh I've done this, though with way smaller logs, works like a charm. If you're worried about the axe breaking, maybe don't use it at all? A good axe can take a lot of punishment.
Not the axe itself breaking but the axe head coming loose from the wood while your exerting lifting force on the two in effort to swing it over your shoulder. Suddenly the lifting force results in the axe flying toward your face before you can react. As I mentioned with the proper technique demonstrated, this should not happen, but if you haven't practiced it enough or you get tired or complacent.. it seems like a recipe for disaster.
It looks safe to me. If the axe broke free the log would fall on the ground beside you. That’s also not a big load for your back and shoulders—certainly not hold it only briefly like that.