JP didn't look all that happy...there was another time that I saw them live, in Detroit for the Sytematic Chaos tour that JP seemed totally aggravated with Portnoy...
They went into In the Presence of Enemies Pt. 1 and Portnoy, Rudess and Myung started and JP wasnt even close to being ready. He missed like the first 4-5 measures and looked over at Portnoy and mouthed a "what the *&%$" and Portnoy just mouthed..."Im sorry" or something like that. It was kinda strange...
I didn't think he would actually smash the guitar, but I guess JP wasn't going to take any chances haha. I saw another video of that and when Portnoy starts swinging the guitar JP just drops the sticks and rushes over there!
check this: [ame="http://www.youtube.com/watch?v=Jln0mVAhpM0&feature=related"]YouTube - Portnoy on Guitar and Petrucci on Drums in Belo Horizonte[/ame]