I always try to keep in mind what my father told me "If you ever pull a weapon, you'd better be ready and willing to use it. Otherwise you may end up eating it."
Personally, I would have probably sprayed him with OC (AKA: pepper spray) when it became apparent he was a physical threat. If a weapon appeared on or about him, then things may have progressed differently.
Kalashnikov Klub #120
A witty saying proves nothing - Voltaire