an average workday at a jewelry exchange quickly turns frightening. but a store manager is ready to face any danger that walks in the door. >> the rob her a knife and a crow bar. he could have hit me, could have killed me. for me, it's like it's either me or him. >> june 28th, 2013, calgary, in canada's alberta province. it's early afternoon and a few customers are doing business in a gold and silver exchange shop run by simon zeiter. >> we sell precious metals, gold and silver bars. we take them off of the stock market and whenever you come into our store you buy and sell f. a customer comes in and he would like to buy some gold or silver we have it in stock. >> the security video is silent but the cameras record whoever is this the store from two