Black Ops 2: is this dude cheating or is it lag?

I have only been playing Xbox live for two months and love it. I am 41, and was getting MURDERED in MW3 by 8 year olds. In Black Ops 2 I seem to do much better. Lately I have had some weird shit happen: glitching, dudes flying, and LAG. All day I hear kids crying "LAG SWITCHER!!" after they get killed. Mostly just whining IMO. But check out this video, I shoot two guys, and as I am about to murder #3, some crazy glitching happens, and I end up dead. Is this guy cheating? Or is it just lag? I really don't know. Let me know what you think.