This scenario begs for some form of empty hand skills. You shouldn't have to draw your weapon as a form of non-lethal force. Empty hand skills enforced properly should give you the distance needed to get out of the situation or incapacitate the attacker regardless of size (for the most part). OC spray could be a good alternative also.
Firefighter/EMT - Currently teamed on Engine 1... I always get to play with my Knob!
"Good judgement comes from experience and experience comes from poor judgement" - Unknown.
"An armed society is a polite society. Manners are good when one may have to back up his acts with his life." - Robert A. Heinlein