Many believe a two-goal lead is the most dangerous in hockey. Others contend a three-goal edge has that distinction. Truth is, the game's most dangerous lead might be any that the Penguins get against Philadelphia at Consol Energy Center. Doesn't matter how large, or how they get it. Getting in front of the Flyers here rarely is a problem. Staying there, as they were reminded in a 6-5 loss Wednesday night, is considerably more difficult.