Lots of scoring and wild action took a back seat Wednesday night to a slash that could lead to a suspension for Canadiens defenseman P.K. Subban. Brian Flynn’s goal was the winner at the end of a wild second period that saw five goals scored and Subban ejected for slashing as Montreal downed the Ottawa Senators 4-3 in the opening game of their NHL playoff series. Montreal takes a 1-0 lead in the best-of-seven Eastern Conference series into Game 2 on Friday night. ”I agree it was a slashing penalty but I don’t agree that it deserved five minutes,” said Montreal coach Michel Therrien.