Vaccilate.

Your concern is very commendable, but the time it takes to express it is sufficiently long for a pair of mean-looking, knife-wielding hoods to show up and attack. Instantly, you spring into action - as, despite his wound, does the stranger. A back-heel to the groin of the smaller of your assailants sidelines him within moments, but the larger one manages to land a fluke punch to your temple with his swastika-tattooed hand and you flop to the ground unconscious...

Regain consciousness a few minutes later.