Her response definitely wasn't less delayed than she felt, but Adrien was trying to think of what was going on. If it wasn't a normal carnival, an akuma was the only possibility he could think of that made sense - but he didn't know yet, and so he couldn't just leave Marinette here to go transform. If they look around together then he can keep her safe that way, until he figures out what's going on.

When she finally answers, he nods after she finishes her stumbling. "Where have you looked so far? I've only been here and to the food." He had to get cheese, after all.