Call of Duty has become much more than a game franchise, it's a global phenomenon. As developers strive to take the game to the next level each year, sometimes a handful of quirks get left by the wayside.
To be honest, sometimes they just flat out don't make sense. Tomahawk + toe hit = instant death? Makes sense...if you follow a different line of logic than the rest of the world. Crazy Penguin has dubbed this 'COD Logic.'