Not sure how accurate this is, but I've read and heard several instances where in an SD situation, the adrenaline is so great, that it shuts your hearing down to the point that there is no damage.
I remember talking to someone years back that was in a situation, and he had no deafness, ringing, etc. after the incident.
:shrug:
However, even before seeing the baseball bat reference, I was thinking crossbow.