Riley Stadel, Tyrell Goulbourne, Rourke Chartier and Cole Linaker also scored for the Rockets, who lead the second-round series 2-0, while Jordon Cooke made 36 saves for the win.
Scott Eansor, Alexander Delnov and Roberts Lipsbergs supplied the scoring for the Thunderbirds.
Seattle's Taran Kozun allowed five goals on 29 shots against.
OIL KINGS 3 WHEAT KINGS 0
EDMONTON — Tristan Jarry won the goaltender battle, stopping 29 shots as the Oil Kings blanked Brandon to go up 2-0 in their second-round matchup.
Jordan Papirny stopped 54-of-57 shots, including 21 in the third period, for the Wheat Kings.
Edgars Kulda had two goals and an assist to lead the Edmonton offence.
Ashton Sautner also scored for the Oil Kings while Brett Pollock tacked on two assists.
ICE 4 TIGERS 2
MEDICINE HAT, Alta. — Rinat Valiev broke a 2-2 deadlock at 13:08 of the third and Jagger Dirk added insurance into an empty net as Kootenay doubled up the Tigers to open its second-round series with a victory.
Jon Martin and Austin Vetterl also scored for the Ice and Mackenzie Skapski made 28 saves for the win.
Marek Langhamer gave Medicine Hat a chance by stopping 38-of-41 shots while Cole Sanford and Trevor Cox each had a goal and an assist.
Jordan Steenbergen of the Tigers and Kootenay's Blake Penner were assessed fighting majors and game misconducts at 19:49 of the third.
WINTERHAWKS 6 ROYALS 3
PORTLAND, Ore. — Oliver Bjorkstrand and Derrick Pouliot each had two goals and an assist as the Winterhawks toppled Victoria for a 2-0 second-round series lead.
Nicolas Petan and Anton Cederholm also scored for Portland and Brendan Leipsic chipped in with three assists.
Steven Hodges scored twice for the Royals and assisted on Austin Carroll's goal as well.
Brendan Burke made 22 saves for the Winterawks while Victoria's Patrik Polivka turned aside 38-of-44 shots in defeat.