I think he should have gave in to the blood lust for panicking Morgana and crying Momo, only to regain control after realising how much influence the vampire transformation has on him but not losing his cool is fine, too.
@welcome2atlantis It's confirmed that silver is their weakness and sunlight weakened their power except their retainers. Plus, the vampires are much stronger than the Moroi.
So momo was able to stop the fight before Keigo ripped her apart for good O_O I really like Keigos dont give a fuck expressions.
ps- the horn thing really needs to start wearing those nappies. And he pisses like a broken hose nozzle.