I carry my surefire when I travel (sometimes 2).. Luckily, I have never needed to use it in such a way. They also have models with bezels that has an impact head which would come in handy (but I don't travel with that one.)

Another tip is to learn some kubuton techniques that can be applied with the torch.

Note that this only applies to a single attacker scenario, and gives you either time to run or counter attack.