hmmm.....me vs bear grillz....and i have a knife....well....he is like a marine or w/e he his....so id think he would win no matter...even if i had the RPC M1B Rocket Propelled Chainsaw
I would jump in the air as the bear is about to kill me and make gang signs at it until i turned into a log, appeared behind him, pulled the knife out of my orange jumpsuit, tapped it against my head band with a metal plate on it, and tossed it at the back of his head hitting him perfectly, felling the bear.
Spread arms, maintain a healthy distance, and holler at the bear to move along... if that doesn't work, chill a bit farther away and then go back and try to move him...
having a father who works at the National Parks = win.
If the bear came at me I would attempt to block any of his movements/her movements with the blade or tip of the knife... Stabbing/cutting > slashing in lethality.
Edit: Bear Grylls was SAS... you know, the British Spec ops?