Backup Weapons

I was speaking with a local police officer recently, we were discussing firearms, of course.  Anyway, we got on the subject of a fire fight and he explained to me, his pistol is what he uses to fight to his patrol car in order to get his rifle.  He takes his stand with his AR15.  His knife is used as a tool, unless he runs out of ammo, and is still getting attacked, he would never rush in with just a knife or a stick.

What are your thoughts on backup weapons?