Trade-offs
I have your word that you will do all in your power to protect the students of Hogwarts?
Hoarse screams pierced through the sounds of battle, and as Snape turned in the pitch dark he made out a shape flailing on the ground. It was thrashing against a jagged remnant of the ruined entrance gate, a sickening thud accompanying each involuntary seizure. A Death Eater stood over it, laughing.
"Stupefy!" Snape cried, and his red bolt of light briefly illuminated the face of Dean Thomas, striking his writhing body squarely in the chest. The student's arching back and neck went instantly limp, and Snape thought he caught a glimpse of blood trickling out from under the boy's ear.
The Death Eater standing over Dean whipped around, raising his wand with furious speed, but they were close enough now to see each other's robes, and the man seemed to double-take as he realized he was facing an ally.
"What the…" he began in confusion, and Snape recognized Dolohov's voice. A flash of spells around them lit their faces in brief, strobe-like bursts, and Dolohov snarled, "Snape? What the hell do you think you're…"
Snape surged forward, grabbing Dolohov's wand arm and pushing him roughly against one of the towering trees a few feet behind them.
"What are you doing?" Dolohov shouted, suspicion and outrage filling his eyes, but Snape leaned close and spoke with cold disdain.
"I could ask you the same thing, Dolohov," he said. "Dawdling over the cannon fodder while the battle remains to be won? Leaving the real threats to us while you practice your moves on unarmed sixteen-year-olds?"
Dolohov's face, already streaked with sweat, flushed ugly and dark. "How dare you!" he shouted, struggling against Snape's grasp. "The Dark Lord gave us specific orders to torture and kill as many of Potter's little friends as possible! You were there, Snape!"
"I was also there when he ordered us to take Hogwarts. You may have dozed off while we discussed that trifling matter, so let me refresh your memory. Our first duty is to secure his victory, and that means defeating the Order. After we have eliminated the qualified wizards, the actual threats – the adults, in other words – we will have unlimited time to do what we please with the rest!"
He sneered and shoved Dolohov once more against the tree's trunk as he stepped away. "Now stop indulging yourself with easy marks and start earning your place in our lord's service. If I see you wasting your time with one more child while our comrades are still falling in combat, I will make sure our master knows of your cowardice." As he began to turn back toward the battle, Snape kept his eye on Dolohov – though the man was shaking with anger, it appeared he was not quite fool enough to draw his wand against one of the Dark Lord's most honored servants. "Pass the word," Snape drawled over his shoulder, nodding slightly to himself as he heard Dolohov stalk away.
Snape swept past Dean's unmoving form and cast a silent spell.
Dolohov fumed for five minutes, then set off to find an Order member.
Dean breathed quietly in and out, unconscious. When he woke an hour later, he was surprised to find himself alive, and even more surprised to find himself invisible. Someone must have cast a Disillusionment Charm over him as he lay helpless on the ground. A dozen Death Eaters had probably brushed by and overlooked him. The battle had moved past him now, closer to the castle. He scrambled in the dirt for a few minutes looking for his wand, then shoved it under his arm as he ran back into danger. He didn't know how much longer the Charm would last, but he intended to take full advantage of it while he could.
He stumbled over something in the dark, and reaching down, he found Professor Lupin.