"Haa..." he exhaled as his eyes opened.
There was nothing but darkness around him.
The moment he parted his lips to speak, an endless pain erupted in his throat and sent him crumpling to the ground immediately.
What is happening?
An endless flood of information about everything within a specific area — with him at the center — came cramming itself directly into his brain all at once.
He was no stranger to pain, sure, he'd felt his share of it before, but never anything like this. Never anything close.
Aaaaargh—!
No voice came out. Every attempt carved his throat open from the inside, like countless needles driving in all at the same time.
What— what is this? Why does it hurt so much?
Saliva seeped from the corner of his mouth and mixed with something sticky against the floor. Yet somehow, even as his body writhed, his mind stayed sharp. Unnervingly sharp.
And then a thought surfaced through the haze of agony.
This perception — this flood of awareness — it revolved entirely around him. He was the center of it. And the pain only came when he tried to speak.
Mute.
He couldn't see, yet he could perceive everything around him with his eyes shut.
Blind. And yet not.
Astral perception.
He knew it probably sounded stupid, but no matter how many times he turned it over in his head, every road led to the same conclusion.
I kept your internal monologue in italics, smoothed the pacing so it builds tension naturally, and broke up the dense block into breathing room so each realization lands harder.