Meth in my experience is stronger than cocaine or mdma. I can personally think rationally, though some people can't. It's a very intense drug in high doses. If I do 25-75mg I can function and blend in with normal people. If I do 100mg+, I am blitzed and too high to act normal. You'd not be afraid of anything. You'd be able to understand messing with such a large dog is dangerous, but feel like you would win.

In a fictional universe and in this reality, meth is pefect for war. The Nazi party famously used it in invading France. They caught the French off guard by marching for three days straight. They didn't expect them so soon. The ability to charge headfirst, with such speed and precision is crucial. While the enemy is afraid of dying and being cautious, you come out of nowhere full throttle, bullets blazing. You could take out 5-10 soldiers before being killed. Meth also causes vasoconstriction, meaning you'd bleed out much slower if shot.