Well, drawing is part of the training that would come in handy here. Ultimately though, you shouldn't draw a gun that you aren't prepared to use. If the other guy has a gun, he may shoot first. If he has a knife, he may charge you.

You might be better off not carrying if you don't train some. I think of it like a life insurance policy, you pay premiums every year. Training is like that, you need to put in the time and money to do it regular enough that it's actually effective when you need it.