The funniest part was when Cartman said "bathroom" to his mother, but not for the reason you may think. The previous episode she had him under control, and threw it all away at the last second. This moment epitomises Cartman's selfish attitude, and for her to do as she did, symbolises her weakness and his contempt for her in return
That said, I felt they could have done more for the ending. Why did they not have Cartman grab the sword and kill Kyle? Afterall, in previous episodes he has enjoyed a theme park by himself, and his life mission is to make Kyle's life a misery. But meh, maybe it would have been too predictable.