Pandora was stunned by the scene before her. The Inferi had already crawled out from the stairwell, reeking of rot as they pressed toward the exit.
She suddenly let out a sharp scream, drew her wand, aimed at the little bag on the ground, and shouted with all her strength:
"Bombarda Maxima!"
Hearing her voice, Snape twisted his body desperately in midair, trying to see whether Pandora had been hurt.
Everything seemed to slow down. He watched helplessly as the little bag quivered under the spell, then flashed white, swelling outward as though air had been blown into it.
Almost at the same moment, Snape reacted instinctively, without thinking, and shouted loudly:
"Protego Maxima!"
An invisible barrier glowing faint blue instantly spread out, enveloping the three of them.
"Boom-"
The explosion was deafening and the once-solid passageway tore apart in an instant as if it were made of paper.
Staircases sank, walls collapsed, stones tumbled, dust filled the air,
the entire castle seemed to shudder in the roar.
The violent shockwave blasted away the magical force clutching Snape's ankle, sending him flying at an angle.
Pandora was just a little ahead of him, also hurled high by the force. She floated like a drifting leaf, about to smash hard into the stone wall of the corridor.
"Incarcerous! Rope Accio!" Snape shouted in panic.
"Ah, , !" Pandora screamed, hurtling uncontrollably toward him.
Using the rebound of catching her, Snape barely managed to adjust his position in midair.
The next moment, both of them crashed heavily to the ground.
Snape felt as though a massive hammer had slammed into his back, the pain unbearable. He could hardly feel his back at all.
"Are you alright?" he forced out, enduring the pain as he unbound the ropes that had snared Pandora, patting her as she lay sprawled across his chest, and asked loudly, "Are you hurt?"
Pandora still seemed shaken by the shock. Her hair was covered in dust, her mouth opened wordlessly.
After helping her to her feet with difficulty, Snape slapped his own head hard, trying to get his buzzing ears back to normal.
As the dust gradually cleared, the devastation of the passage was revealed.
The secret tunnel was riddled with holes; the stairs had vanished completely, leaving only piles of rubble and shards of shattered mirrors.
A few pale Inferi limbs twitched feebly. One half-bodied Inferius, puppet-like, was still struggling to crawl toward them, dragging a deep black trail behind it.
Snape pinned its remaining arm under a rock, leaving it to flail uselessly, unable to approach further.
"Where's James?"
The thought struck him, his heart tightening. He quickly looked around.
At last, he spotted James in a corner.
James lay silently on the ground, blood streaming down from his forehead, running along his cheek. One arm was bent at an unnatural angle.
"Episkey." Snape swung his wand, casting the healing charm.
The gash on James's forehead sealed quickly.
Then Snape bent down again, tapped James's twisted right arm with his wand, and incanted:
"Splinting Spell."
Bandages wound themselves tightly around, binding James's arm to a thin wooden board.
James gave a faint groan, showing signs of consciousness.
Snape checked his breathing, then raised his hand and slapped him across the face.
"Hey, wake up."
James weakly opened his eyes, his face pale from pain.
His gaze was unfocused as he blearily stared at Snape, instinctively reaching up to touch his face.
"Don't touch it, you just smashed your face," Snape snapped.
"Do you know you almost caused a disaster?
"I saved your life, James Potter, do you understand? I saved your life!"
Before James could reply, a rush of hurried footsteps sounded. Professors, still in their night robes, had rushed over.
At the front was Professor McGonagall. Her face was stern, lips tightly pursed, her eyes full of authority and urgency.
Short Professor Flitwick, the plump Professor Slughorn, and the gray-haired Professor Wilhelmina Grubbly-Plank all followed close behind at a brisk pace.
"What is going on here?" McGonagall demanded in disbelief at the chaotic ruin before her. "Snape! Potter! Why is it you two again?
"Fross, why are you here as well?
"Who did this!"
She looked on the verge of fainting from fury, her trembling finger jabbing back and forth at Snape and James.
The trapped Inferius twitched, making a noise.
"What is that thing?" McGonagall shrieked.
"Inferius," Professor Grubbly-Plank crouched down, examining the writhing corpse carefully, her face grim. "Not ordinary Inferi. Weaker than usual."
"What do you mean, Wilhelmina?" McGonagall pressed.
"They weren't made from fresh corpses," Grubbly-Plank sniffed, frowning with disgust. "These Inferi were already rotting."
"They don't have the skill to create these," she stood and pointed at the three students. "I think you had better explain exactly what happened."
"We should seal this place first," McGonagall said.
Beams of light flashed, magical wards quickly enclosing the ruined passage, sealing it off from entry or exit.
"Professor McGonagall," caretaker Filch came huffing and puffing, his sallow face red from running, "what happened, was it troublemakers again?"
He glared venomously at James and Snape with his beady eyes.
"Outrageous! No thought at all for the workload you cause me!"
Just then, a peal of urgent bells rang out from afar, echoing unnaturally loud in the quiet night.
It was coming from the direction of Hogsmeade.
The professors' faces suddenly grew tense.
McGonagall paced anxiously in place, clearly hesitating.
"Argus," she finally decided, "you take these three to the hospital wing.
"Horace, Wilhelmina, the school is in your hands, protect the students, get the prefects to gather them in the Great Hall.
"Filius, the situation is critical. You're a dueling champion, come with me to Hogsmeade."
The faculty each accepted their tasks and acted swiftly.
"Where is Professor Dumbledore?" Snape called after McGonagall's retreating back.
But there was no reply.
McGonagall hurried away, her figure vanishing around the corner.
The peal of Hogsmeade's bells still echoed over the castle.
....
TL Note: We never actually got to know the maiden name of Pandora, so I just picked one since the transliteration didn't make sense.