Why was John Dillinger killed by FBI agents in Chicago in July of 1934?

J Edgar Hoover told his agents not to put themselves in harm's way and to open fire at the first sign of resistance. Dillinger sees the agents and puts one of his hands into his pocket. Cops then and now are trained to believe that if someone does that then they are most likely reaching for a gun. (How many news stories have you read where someone reaches for something in their pocket, gets blasted by cops and the cops find out the person is reaching for a cell phone or wallet?). Dillinger was, in fact, reaching for his gun but didn't pull it or point it at the agents. Anyway, Dillinger reaches into his pocket and takes off running to escape the agents. Now if you're labeled "armed and dangerous", reach for a weapon or what cops think might be a weapon, and also run away from them, then you're liable to get shot at and, in Dillinger's case, killed.