After an armed man pointed a gun at the head of 60-year-old convenience store clerk Ibrahim Rahmoun, he and his boss grabbed a gun and took action leading to an exchange of gunfire outside a Northwest Side 7-Eleven. “The guy shot two bullets at us,’’ Rahmoun said. “We shot back at them. We shot eight.’’ “I wasn’t scared. ... I don’t care, it doesn’t bother me. When you work the night shift, a lot of robberies happen’’ said Rahmoun, who was at the counter when two men entered the 7-Eleven at 2900 W. Montrose Ave. about 1:25 a.m. Friday and...