Can you stop someone bleeding out by cauterizing the wound?!

Theoretically, yes, you could. Cauterization was often used on the battlefield in days gone by to save the lives of sodliers who were bleeding profusely. The trick is that you would probably need some medical training to do it in a way that worked.

http://science.jrank.org/pages/1285/Caut…

If the tourniquet doesn't work, you don't have it on tight enough. You can use anything really to make one, rubber tubing, your belt, etc etc. Just tighten it as much as you can and leave your lighter in your pocket.

I'm a Paramedic.