In truth, Penny saw only one reason that he could be uncomfortable with the situation; she'd seen it the moment she'd asked the question and that's why his answer had been stopped before it could come. She knew and he didn't need to say it. Let him think that she wasn't intuitive enough to glean the answer from his very obvious scowl.
"I understand," Penelope said, fighting the urge to say something more. She stood up and, making a very quick decision, strode behind his desk. Before he could object, Penny leaned down and kissed him on the top of his head, smoothing the bright red hair as she did so. Appropriate workplace behaviour be damned. It wasn't quick, but she didn't linger, either and soon stood at his door, hand on the doorknob. "See you tomorrow most likely, yeah?" she said with a small smile as she pushed the door open and left, feeling much better than she had in days.