Miles Koules opened the scoring for the Tigers at 8:10 of the first period.
Jon Martin scored at 15:46 of the third for the Ice, who led the series 3-1 before dropping back-to-back outings.
Medicine Hat's Marek Langhamer made 26 saves for the win as Kootenay's Mackenzie Skapski turned aside 28-of-30 shots in defeat.
The Tigers will host Game 7 on Wednesday. The winner will face the Edmonton Oil Kings in Round 3.