Hunter Shinkaruk scored once and set up four others for the Tigers (6-8-1), while Boston Leier, Ty Stanton, Dylan Bredo, Chad Labelle and Gavin Broadhead also scored.
Dylan Busenius, Tyler Lewington, Kyle Becker, Derek Ryckman and Spenser Jensen all chipped in with two assists each.
Cody Sylvester scored the lone goal of the game for the Hitmen (8-3-2).
Cam Lanigan made 24 saves for the win.
Chris Driedger started in net for the Hitmen and stopped nine of the 13 shots he faced before he was relieved by rookie netminder Mack Shields at 4:50 of the second period. Shields finished the game with 14 saves.
The Tigers led 2-0 after the first period on goals by Leier and Shinkaruk.
Medicine Hat then erupted for five goals in the second, three of them off the stick of Valk. Stanton and Bredo also scored in the middle period as the Tigers built up a 7-0 lead.
Labelle and Valk scored early in the third before Sylvester finally broke Lanigan’s shut-out bid at 14:13.
Broadhead then rounded out the scoring for Medicine Hat at 19:14.
The Tigers went 4-for-10 with the man advantage, while the Hitmen failed to score on five power-play chances.