Simon Gagne didn't know his nickname in Boston is "Bruin killer.'' Yesterday, though, the Lightning forward solidified his status as one of the most hated players to Black and Gold fans when he scored the winning goal in Game 4 of the Eastern Conference finals. Gagne's goal came at 6:54 of the third period when he took a pass from Ryan Malone and beat Tim Thomas through the five-hole from the slot, the go-ahead strike in the Lightning's 5-3 victory.