Curious Wave at the Edge

A guy stands at the edge of a moving escalator, waving with one hand to get attention, while the other hand holds up a question mark. It's like he's saying, 'Hey, I'm here, and I've got something to ask.' You'd use this picture if someone's trying to speak up in the middle of a busy moment or when they're ready to ask a question but don't want to shout it out.