There is one simple way to kill Sam! It is necessary to dry out a bit because of the corner and sharply hide, so that Sam is aiming (usually it is worth dropping Thompson), you must stand around the corner and watch Sam (thanks to the chamber from a third party :-)). Sam will look in your direction, but then turns sideways to you, wait again and it turns his back! And so!!! Moment when your task quickly feed his lead!!! Then run after him, and when he populates from behind the corner, it is no longer difficult!