Krav Maga is different from traditional martial arts in several ways, but most importantly it aims to avoid fighting if possible. The only street fights you win are the ones you avoid. If this is not possible the emphasis shifts to ending it as fast and efficiently as possible, leaving and going home safely.
I quite like this definiton of Krav Maga from the Army Rumour service:
“Israeli Japslapping. Please do not confuse Krav Maga with martial arts of the conventional or oriental variety. There is no philosophy involved here except for one – give your opponent an unbelievably brutal shoeing as quickly as possible to prevent the bugger from brutally shoeing you first.
A pretty good philosophy if survival is your aim. The theory is that if it works, use it. High kicks, complicated manouvers and impractical techniques are stripped out and operates on a bare minimum needed to get the job done.”