Clara would recognize that uniform anywhere by now, she spends far too much time with Jim and by proxy Spock and Bones, not to instantly connect it with Star Fleet. But she hasn't seen this one around before and judging by his expression (and lack of shoes) he's likely just arrived.

She finishes up her business at the stall, picks up her turtle egg (she's currently on duty), and rushes off after him. Thankfully, the uniform makes him easy to spot and she ducks under a few people's arms that are reaching for merchandise to catch up with him. Finally, she walks next to him, but needs to walk swiftly to match his stride.

"Let me guess, coming here isn't Star Fleet business."