John Chambers was clear at the other end of the hall at The Dalles High School when he heard the bam of someone getting slammed, hard, into a locker. The slamee was John Callahan, the eventually famous cartoonist whose life story is told in the recently released movie, “Don’t Worry, He Won’t Get Far on Foot,” which opens Friday, Aug. 24, at Columbia Cinemas in The Dalles.