A UFC fighter would definitely be concerned about a junky with a knife, because one mistake could have dire consequences, even if the odds were wildly in his favor.
Both combatants can be terrified, because being the odds-on favorite doesn’t mean you’ll come out of it okay.
You get terrified of the battle, feel it in your chest; both are the same, just armed differently. Whatever is thumping in the brain, fight or flight. It would be a bummer to have take on a guy in armor having only a knife, though it's the soldier that makes the infantryman, not the rifle. My Dad getting bayoneted knew he'd lost taking on three other guys, he shot one, clubbed the other to death with his rifle, and was got by the third. Hell of a way to be a kid. Sun Tzu said thousands of years ago: "On death ground fight."
