I would hate to go against a mountain lion with a knife, although it has been done before (successfully even).
I remember a few years back a logger on Vancouver Island walking down a logging road was jumped by a cougar and he was able to turn on it and kill it with his pocket knife. Wow!
I would even hate to go against a couple of pitbulls with a knife.
Like Rumsfeld said, "You go to war with what you've got," but the more substantial the better.
I always carry a knife especially when I'm going where I can't carry a gun, and if I go where I can carry neither, I feel downright naked.
Maybe this woman used to work in one of those Japanese steak houses where they really know how to use knives. She obviously got a helluva job done! Probably helps to know where the critical veins are. I’d hit fat or flesh only.