A point guard, McMahon ended his collegiate career with Eastern Washington Universitycollege basketball's second best steals getter, with a 3.52 average per game, 225 over his 3-year career, an average that trails only Mookie Blaylock's 3.8. McMahon's 9 steals in a December, 1989 game against Portland State is a school all-time record. He was named to the Big Sky all-conference first-team for 1990. He was a top three rated player for the school between 1980 and 1994. He stood as of January 2006 the Big Sky's 14th career assist leader with 421.