Harry screamed, running forward. "No, stop, Harry. This is between me and the Professor." Lily said. An invisible force knocked him to the ground, and he saw Lily, standing with several cuts on her body. Snape had pointed his wand directly at his head, and Harry grimaced, unable to get up.
"Don't get any closer." Snape said, voice rising. Lily walked forward, stumbling as several more cuts appeared on her face. They were deep, Harry could see, cutting to the bone. He struggled, punching and kicking against the invisible force that held him down.
Stop, Harry. You can't help in the state you're in. He heard Magnus say.
"Please, Severus. I didn't mean to-" She tried.
He cut her off. "What you meant, was meaningless. Now get out before I kill you. GET OUT!" He roared.
I can't! He screamed internally. I have to! She's my mother! He's going to kill her!
Harry saw her continue walking, the cuts getting deeper and deeper. "I know you care about me, Severus. Please don't do this." She said, some moisture dripping down her cheek. Harry thought it was blood, but blood never glistened like that. It was a tear.
Don't worry, he won't, believe me. He heard Magnus say.
Harry struggled more, trying to feel his way around the invisible force that bound him using his magic to no avail. It was like trying to lift a mountain off of the ground, impossible and foolhardy.
He didn't respond, silently raising his wand once more. "I'm sorry Severus, I… I really should have-" She fell, blood gurgling from her mouth and drowning out her words. Harry screamed again, pushing with all his strength but unable to stand.
The spell broke. Harry ran forward, clutching her mother's body in the pile of blood that streamed onto the floor in a river. He saw Snape approach, and snarled, trying to cast a spell with his hands. A weak fizzle of light was all he could manage.
Snape dropped to his knees, and began healing her. Horror had clouded his eyes, and his wand jerked in his hand as if wanting to leave.
"No, no, no." He heard him say.
Harry saw Lily open her eyes, and her mouth opened as if to speak, but then closed. The cuts and scrapes began fading away, but her blood still pooled on the floor. Her face had turned pale, whiter than the snow during winter.
She sputtered, trying to say something. Snape hurried to his desk, uncorking a potion of sorts. It's liquid was as red as blood, and some of it spilled as he hurried over, pressing it to her lips. Some color returned to her face as she drank, her eyes focusing on Snape. Harry watched, wanting to attack but not interrupt. So he sat there. His scar was glowing, pulsing with the green light that he remembered from the killing curse.
Magnus began prodding at his head, trying to take control. Harry let him, his mind numb. As he lost power his eyes glowed an unnatural green, like a streetlight switching colors. They shone through the dark dungeon like the eyes of a demon, looking at Snape with a glare nothing short of menacing.
"Oh Lily, Lily! I'm sorry, I didn't-" He tried, but she cut him off this time.
"I know what you meant, Severus. It's fine. Harry, clean up for us will you? We wouldn't want anyone seeing this." She gestured at the blood.
The glow in his eyes faded as Magnus left, and Harry grabbed his wand. "Scourify." He said, pointing towards the ground. His eyes never left Snape.
"I'm sorry for how I acted when I was younger. I never really thanked you either. You were a good friend, Severus." Lily said. Her eyes were glazed over. She yawned, as if sleepy. "I asked for a potion, and you gave me the wrong one. Take me to the infirmary. I'll be fine, take care of Harry, will you? I'll be back soon." She said.
Snape gave a limp nod before she passed out.