In the second period of their first preseason contest against the Boston Fleet, the Montreal Victoire took a penalty.

But instead of bringing on the team's first penalty killing unit, the players on the ice were stuck. The team wasn't allowed to change lines until after the first face-off, leaving Boston to match up its top power play unit with three Montreal forwards and a defender, none of whom are typically first-unit penalty killers.

The tired Montreal players got stuck on the ice for the full two-minute kill, a massive advantage for Boston on the power play.

Welcome to the PWHL's new "no escape" rule.

It's one of several changes the league has made to try to improve play in its second year. In this case, it's aimed at increasing scoring in a league where goals were hard to come by last season.

For players, it means every person needs to be prepared to kill penalties at any time. At one point on a penalty kill in the game against the Fleet, Montreal forward Mikyla Grant-Mentis, typically an offensive specialist, found herself playing defence.

"I would never want Grant-Mentis to play D," Victoire head coach Kori Cheverie said after the game, which Boston won 3-1. "She needs to score goals. She doesn't need to stop them."

The idea came from the league's rules and competition committee, chaired by league advisors and retired players, Cassie Campbell-Pascall and Meghan Duggan. 

When they dug into data from last season, Hefford said league-wide scoring on the power play stood out. Power play efficiency was around 16 per cent, lower than the NHL average of 21 per cent.

"Sixteen per cent feels low," Hefford said in an interview with CBC Sports. "It feels like we can do better than that."

From 'jailbreak' to 'no escape'

Trying different things has been a hallmark of the new league. First, there was the "jailbreak" goal, where a shorthanded goal frees the player from the penalty box.

Then, the league let the team that finished atop the standings select its first-round playoff opponent among the third- and fourth-best teams.

The league may not keep every new rule, but they're not afraid to try things and make mistakes, Hefford said.

"We don't have to do it the way it's always been done, and we aren't just trying to be the NHL," Hefford said. "How can we make the game more engaging for fans is always a priority."

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Players and coaches learned about the new rule within the last few days, forcing them to adapt on the fly over preseason games this week.

For a team like the Boston Fleet, which struggled to score throughout last season, it could provide opportunity. But it requires adaptation on the defensive side of the game.

Boston head coach Courtney Kessel said both her team and Montreal "tried some tricks" in the first game with the new rule. But trying to game the system won't fly.

The rulebook says a team will receive a delay of game penalty if the team "intentionally places too many players on the ice to cause a stoppage of play and create confusion about which players must remain on the ice in the application of the new rule."

Automatic game misconduct for illegal hits to head

In Montreal, Cheverie wasn't sure what to think of the new rule yet. As a fan of order, it has forced some chaos into Cheverie's brain mid-game.

Cheverie's coaching specialty is the penalty kill, and she wonders how it will change the job for those players.

"I think that the purpose behind it is to create more scoring and that's OK, but I do really value the PK players on our team," she said. 

"With the jailbreak goal and now this rule about the PK, what role do our PK players have? We're taking more jobs away from players. We're taking roles away from players."

There's also a league-wide drive to crack down on hits to the head. An illegal hit to the head will automatically result in a major penalty and game misconduct, and will result in a review with the league's central situation room.

While the PWHL has embraced more physical play, Hefford is adamant that there's no place for hits to the head.

"Considering the increase in physicality, there was nothing that alarmed us to do this," Hefford said.

"I think it's just more generally as a hockey fan, we want the best players playing the game. We want to take care of everyone's safety no matter who it is on the ice, and we're just going to make sure that we get that right and we do everything we can to deter those kind of hits."

After preseason games in Montreal and Toronto this week, GMs and coaches have the weekend to make their final roster decisions. Waivers will open on Tuesday at 5 p.m. ET, and teams must have their rosters finalized by Wednesday at the same time.

Teams can have 23 players on standard contracts, plus three reserve players.

The regular-season will kick off on Saturday with the Toronto Sceptres hosting the Boston Fleet at 2 p.m. ET at Coca-Cola Coliseum. The game will be streamed on CBCSports.ca, CBC Gem, and CBC Sports App.