Honestly, Duo doesn't seem bothered by the situation at all. Sure, he's pouting, but since he's already cheerfully laughing again a moment later, it makes the pout seem a lot less genuinely upset.

But despite his reaction, Alice looks lost for words for a moment. By the time the girl actually speaks up, there's something very genuinely guilty in her gaze when she looks up from the sand to meet Duo's eyes.

"Duo, I'm.. I'm sorry."

Usually Alice wouldn't bother to apologize, but this is different. She likes Duo! And the last thing she wants is for him to think of her as someone irredeemably and unpredictably violent like most people do.