"And I suppose you didn't tell him about me, either?"
"Um, of course not?" Harry said. "I've been doing science with him since October, and he wasn't exactly ready to hear about you then -"
The inexpressible sense of betrayal inside her was welling and welling, taking over everything, her rising voice, her glaring eyes, her nose that she was certain was starting to run, the burning in her throat. She shoved herself up from the table and took a step back, the better to look down on her betrayer, and her voice was very nearly screeching as she yelled, "That is not okay! You can't do science with two people at once!"
"Er -"
"I mean, you can't do science with two different people and not tell them about each other!"
"Ah..." Harry said cautiously. "I did think of that, and I was very careful not to get your research mixed together with anything I did with him -"
"You were being careful." She would have hissed it, if it had contained any Ss.
Harry raised a hand and rubbed at his messy hair, and somehow that made her want to scream at him even more. "Miss Granger," said Harry, "I think this conversation has become metaphorical on a level that's, um..."