Bad idea: holding up a store clerk who happens to be proficient in firearms.Worse idea: holding up a store clerk who is not only proficient in firearms, but who also happens to be an Iraq war veteran and a former prison guard and private investigator.Jon Lewis Alexander, 54, is no ordinary store clerk. He has worked several “high risk” jobs and served four tours of duty in Iraq during his 30 years in the U.S. military.And his training shows.Video surveillance from Saturday night captures the moment a would-be thief entered the Marionville, Mo., store where Alexander works. The thief hesitates for a moment and pulls a gun — but not fast enough to dissuade Alexander from pulling his own Walther PPX 9 mm handgun and sticking it in the hapless thief’s mouth.No one was hurt and no shots were fired.“One of the policemen told me later, ‘You’re a lucky man,’” Alexander told News-Leader.com Monday. “I said, ‘I think he (the robber) is a little luckier than I am.’ ”Alexander said the man walked in smoking a cigarette, which he was promptly told to put out. The thief then reached for his gun and demanded “all the (expletive deleted) money,” News-Leader.com reports.The veteran reacted quickly, throwing down the thief’s arm. Alexander tehn drew his own weapon and, according to the report, threatened to “blow his (expletive deleted) head off.”Pistol at his side, the thief backed away slowly and then bolted from the store. The store clerk remembers being amused by the fact that he “didn’t even bother holstering his weapon.”Dawson fully supports Alexander’s handling of the situation, saying “I think it’s a great thing.”Meanwhile, the store clerk explains that he never fired a shot because the thief’s weapon was never pointed directly at him.“If I had seen the actual barrel of the gun, I would have pulled the trigger,” he said. “My life wasn’t threatened.”He adds that he didn’t immediately tell his wife, Pam, about the incident because he didn’t want to upset her. However, she eventually saw a copy of the surveillance footage.“It took her a while to calm down,” he said. “But I got all kinds of lovin’ when she came home.”The store’s owners have since turned the video over to the police. Law enforcement officials have not yet caught the suspect but they hope for a quick arrest.