Snape wanted to shake his head, mostly at himself. Growing up as he had, he'd learned early in life that people didn't make sense. It was why he watched them so intently. He needed to know, always had, just what people were thinking. Because, if he didn't even know that, he couldn't shape their thoughts. A smile, an earnest expression, a muttered word just loud enough to be overheard.
The heart of it was, Snape had instincts, his own gut reactions that told him what people would do.
They were always wrong.
Snape had gotten used to ignoring them, squelching them - reading people instead of trying to predict them through his own behavior.
It never worked, anyhow.
Except this was exactly what Snape would have done, given the same circumstance. Told nothing, he would have said nothing. Certainly, Snape knew he'd have picked up on the Gryffindor unrest (if he'd ever been that foolhardy to be sorted there! Worlds would have burnt to ash!). But Snape wouldn't have surprised himself by finding a quiet corner to think over the situation.
This once, he should have listened to his instincts. Potter had been decently good about keeping his trap shut, in general. Snape wondered how much the Gryffindors knew about Potter's training - certainly Granger knew something, because she'd shown up for training of her own. Maybe she even believed that Snape gave out detentions.
Nobody ever believed him when he said there were worse things in life than detentions.
"What shall we tell them, Mister Potter," Snape said smoothly, "That you suffered an unfortunate mishap? That your foolhardiness led to you knocking over one glass jar too many?" If only this was Tonks, it would make this easier.
Potter looked back, "I'm not sure they'd believe you."
McGonagall spoke up, her voice thick with Scotch, "Dinna ken why ye can't shaddap and let yer elders think."
Snape looked over at her, and fell silent. Potter, mercifully, kept up with Snape's cue.
McGonagall smiled, and it was a catty thing, full of canary. "I've got it! Snape, you'll be 'disciplined' for Potter's unfortunate cleaning accident. Mayhaps you weren't payin' enou' attention to your detention? Busy with your own Potions, and too deep into it to hear Potter screamin'? We'll be watching you closer, right we will. And Dumbledore had a word with you about your treatment of Potter..."
Potter spoke up, "Not me. Neville."
Snape's eyes shot to Potter. "How would we explain that?"
Potter grinned, "Professors Dumbledore and McGonagall had a word with you about your treatment of the Gryffindors. You've said that you'll treat us more fairly - but your bile keeps on boiling over at me. If you can refrain from calling Hermione a know-it-all."
Snape snorted at this.
Potter assuaged, his eyes leaping with delight at his plan, "Oh, you can still refer to her effusive test-taking, just don't name-call."
Snape nodded at this.
McGonagall said, "Potter, you need to be able to believably say that you were embarrassed."
Potter nodded, "Yeah, I can say that. And I can say that if I'd spoken up earlier, I would have just gotten everyone riled up."
Snape's eyes looked at Potter. I do have to admit, it would be possible to rile them further.
Prof. Dumbledore's eyes twinkled, as he looked at his pupils. "Very good. Harry, perhaps if you were to talk with your housemates as soon as possible?"
Harry stood, and made as if to dash off up half a dozen flights of stairs.
"Mister Potter" McGonagall said, "I'll join you. You wouldn't have any reason to know of Snape's punishment."
They had left, and it was like a curtain fell on the kindly old man. Dumbledore looked at Snape with the eyes of a battlefield general.
"When were you planning on telling me you were still training Harry?" Dumbledore asked, looking weary and dead-set.
"Never," Snape smirked.
Dumbledore said, "Do you not think it important that I know the capabilities of my forces?"
"Of course, sir," Snape said levelly, "But everyone deserves a rabbit. And a black top hat."
In the end, there was very little Dumbledore could say to that.
[a/n: Present Potter a problem, and he looks for a solution. Give a review?
Snape's last line was entirely improvisational.
Title's a reference to "You dodge left, when everyone else dodges right."
Yes, of course, Snape is aware why Potter's responses mimick his own.]