As promised, here is my official revision: if you'd like to skip ahead, I've underlined the changed parts. I think this works a lot better!
She walked down the tunnel with great trepidation, casting the beam of light about with quick, nervous gestures, the cold stone floor rough beneath her toes.
The passage culminated in a portal: a pure black oval that swallowed the light from her torch as if she had pointed it up into the night sky. It hung in midair, thin as a pane of glass, not quite touching the wall behind it. Unsure what to do, and not willing to touch it, she probed the darkness with the tip of the machete. From the other side a great force pulled on the blade, and before she could let go she was pulled into the void entirely.
She found herself lying flat on her back, squinting up into a bright sun hanging overhead; a great headache surged through her temples, setting her ears to ringing. Pulling herself to her feet, she was surprised to see she was no longer in the hallway or even the house; she stood in an open field, verdant grass speckled with the bright purples and yellows of wildflowers growing waist-high.
A trail of gore was here, however, matting down the grass; something heavy had been dragged along, and she followed the bloody path to the edge of a thin, trickling stream. On the far side the monster crouched over a great hunk of flesh, tearing off gobbets of meat and shoving them into its mouth. It raised its head up and looked her in the eye as she approached, gore dripping from its fangs; she stepped back, afraid, brandishing the machete.
"You are nothing," it said, disdain tinging its deep baritone. "Run, if you like. The thrill is in the chase, after all."
It smiled before bending its head back over its meal.
A horrible rage possessed her and she rushed across the shallow river, bringing the machete down hard; the blade lodged deep into the creatures shoulder. The monster looked up at her calmly before backhanding her, sending her sprawling onto her backside in a daze.
Images swum before her eyes: thousands of spiders crawling from the shadowy corners of her wardrobe; a child playing innocently in his room as a monster peered out from the shadows; her father’s face, scowling with disapproval; it was a look she recognized, one he'd wear when she'd done something wrong, one that preceded him sending her to her room in terror to await the lash of his belt across her backside. His face transformed back into the monster, and he was biting down into her shoulder, hard, crunching her bones with his teeth. She screamed.
She came to in the boy's bedroom, lying halfway out of his wardrobe closet. Paramedics lifted her up onto a stretcher as a Police officer, seeing her awake, began to read her her Miranda rights. She started to thrash, panicked.
"Don't move," said the Paramedic. "You've been shot, you need to lie still."
"I don't understand."
"Let me clear it up for you," said the Cop. "You broke into this poor family's house and chopped their kid up into pieces with a machete. The Dad found you and shot you before you could murder anyone else in their sleep."
"No! There was a monster! I was following a monster..."
"Get this lunatic out of here," the Cop said to the Paramedic, and they wheeled her out into the waiting ambulance.
"Wake up," she said, fighting against the restraints. "Wake up! None of this is real.”
The doors to the ambulance slammed shut and the Cop sat in the corner watching her, arms folded, wearing the deep, disapproving scowl of her father.
“It’s not real, it’s not real, it’s not real,” she chanted to herself as the ambulance pulled away, siren wailing.