She had to bite back the urge to laugh, the mischievous child in her pleased at having caused such a disruption. But then again, it was more than a little strange to find someone working not only this late, but in complete darkness. Clicking the flashlight off with an easy motion born of familiarity, she quickly holstered it in her belt and curled the thumb of her right hand through the belt loop nearest to the mechanical torch.
"And who're you? Really, I'm gonna need to hear a damned good excuse to not kick you outta here. Let's see some badge or ID?" The usual niceties of 'sir' and 'please' weren't really in Charlie's vocabulary, and thus they had no part in her speech. Her eyes took in the man carefully, going from top downward, and for the most part he certainly didn't look the part of a thief. But then again, thieves came in all sizes and shapes, and for all she knew, he could be some white-collar criminal stealing who knew what from the company. And even if he was (or wasn't) taking anything, she was simply pleased to be given some form of entertainment rather than being stuck in a building all alone.
"And I'd watch that tone, if I were you," she added, the faintest trace of a smirk coloring the edges of her mouth; there was no way in hell that she was going to let him off easily, not if he was the only one in the building and her sole source of human contact for the evening.