The gunman didn't continue running after turning the corner; he slowed down, stopped, and then turned to prepare an ambush for Jimmy behind the corner.
Unfortunately for him, tactics that would work on an ordinary person were ineffective against Jimmy, whose clairvoyant ability had already seen the gunman's move. Jimmy didn't slow down much, and his heavy footsteps steadily approached the corner.
After estimating Jimmy's location, the gunman raised his hand to aim at the corner, waiting for Jimmy to come running by. Jimmy didn't disappoint him; when he got close to the corner, he immediately stopped his run and began to move quietly towards the corner. His revolver was continuously aimed at the position, ready to fire the moment the gunman showed himself.
When Jimmy stopped, the gunman realized something was wrong; the other man was as cunning as they come, not daring to come around the corner, which was very unfavorable for the standoff.