I learned a bit myself just from making this video. Knifing zombies in lag is a little bit different because you cannot always tell where it is, but it's still generally safe if you can get behind it. Knifing zombies in a group is pretty impossible, though. Even David's 4th hit in the knife combo may only knock down one zombie at a time. If the zombies are spaced out around the spin, then it could knock down multiple zombies. You can see clearly in David's part, that if you find yourself in front of a zombie, you can cancel their attacks just by knifing. It's dangerous to try and run away until the zombie sways. I didn't include Mark and Jim because they don't really have anything special to dodge zombies and counterattack afterwards. Jim can flop and get up behind a zombie, but only if the zombie does that weird walking animation that shows they've lost their target. I was really goofing around by the time I got to Cindy, which is why she gets hurt so much..