This content is supported by American Assassin, out in theatres on Thursday, September 14.It'll be fun, they said. When the VICE higher-ups told me that they wanted me to learn how to fight like a trained killer, I thought, at the very least, it'd be a good excuse to get out of the office for a day. When, halfway through my training, I had collapsed face first on the floor of the gym, my arms too tired to support the weight of my body any longer, I began to doubt the wisdom of my earlier evaluation.Close quarter battle (CQB) is the fighting system of choice for the NZSAS. It's all about doing harm as efficiently as possible, with none of the regard for aesthetics you find in traditional martial arts. What you want to do, if someone comes at you with a knife or a bayonet, probably isn't some graceful acrobatic kick; more likely, you'll want to incapacitate your attacker with a knee to the groin, or parry the blow, step to one side, and then use the hard bones of your forearm to choke them out.Barehanded killing is just one skill elite soldiers will master before heading into mortal combat, and the one that trainer Richie Hardcore was tasked with teaching me. With the aid of an up-and-coming kickboxer almost twice my weight.