Some days, killer whales just wake up on the wrong side of the pool. A 2 1/2-ton orca that dragged a trainer underwater during a show at SeaWorld may have been put out by a spat with another whale, grumpy because of the weather or just irritable from a stomach ache, according to marine mammal experts. "Some mornings they just wake up not as willing to do the show as others," said Ken Balcomb, director of the Center for Whale Research in Friday Harbor, Wash. "If the trainer doesn't recognize it's not a good day, this will happen."