"Yes, I'm well aware," she said, crossing her arms loosely over her chest and leaning against the door. "But there's also a reason the professors are doing rounds at the moment instead of students, and that would be due to the late hour. Your rounds have been finished for ages."
No such luck for Tonks being clueless. She may have given off the air of being such quite well, but she underneath that naive exterior, she was more intelligent than others usually gave her credit for.
"I'm in the loo because I've seven extra kilos pressing up against my bladder, and I made the mistake of taking a sip of water before leaving for patrol," she said. "Same reason as you, I'm sure."