The boy guarding the backstage entrance starts to challenge X, but he knows Duo's face; a short exchange establishes that X is an allowed guest too, and he lets them by.

Trowa, backstage, has wiped off most of the discreet greasepaint and neo-mag -- in the future, some merciful person has invented a kind that's easier to get off -- and switched his spandex for jeans and a tank top. (The turtleneck will wait until he's had more of a cooldown, and also a shower.)

He was, in fact, starting to head for the lions' tent, but he pauses when Duo and X enter.