What we learned: Frustration mounts for Bruins in Game 4 loss to Islanders

The Boston Bruins didn’t develop as many quality scoring chances against a physical New York Islanders bunch in Game 4 Saturday night. Even when they did, Bruce Cassidy’s squad failed to convert on signifcant opportunities aside from David Krejci’s second-period power play marker.

Tuukka Rask did all he could in net to keep Boston’s chances alive. The Bruins battled on without a pair of stout right-shot defensemen in Brandon Carlo and Kevan Miller. They witnessed two periods’ worth of head-scratching officiating on both sides. And, they hardly found any space to work with against the trap-happy Islanders.

With a hostile Nassau Coliseum crowd cheering them on, the Isles made their 60-minute…