He followed the sound. Not even his footfalls made a noise as he crossed the empty chamber, eyes darting in all directions but intensely focused on the path ahead. The chamber had two doors, and he moved to the left one on instinct.
He pried the door open and slipped through, and his HUD indicated he was going in the right direction. He could make out a vague shape through the infrared from Scot, and he pushed forward.
The throbbing got louder as he moved further into the temple. He tracked it, gliding from room to room—all of which were bafflingly empty of anything—turning the other way when the sound got quieter. For ages, he went into a room, cased it, and moved on.
"I think you're just about there," Scot said quietly into his helmet. "There's a large room straight ahead that has a figure inside. They're close to the floor, possibly hunched over. Likely unconscious. Be vigilant."
Warren stopped. The rhythmic throbbing sound he'd been following was the loudest it'd ever been, encased in the corners and the ceiling, pounding through the air, and sweat began to form on his brow as his stomach rolled. Breath shallow and staring in silence at the unmoving door, he mentally placed why that sound had been so familiar to him.
"It's him," he said into his helmet. He swallowed the foulness sneaking up his throat. "He's inside the room."
"That's what we suspect."
"No, I know." Warren flexed his grip on the rifle. "It's him."
Thoeala's voice came through next. "How are you so sure?"
"Because I'm standing here listening to his heartbeat within the walls of the fucking building."
Their voices disappeared and Warren was forced to hear it over and over; the slow, unmistakable thump of Thrive's heart. Slower than a human heart, stronger than most. Permeating the entirety of the building as if on a speaker, as if it fed the building's foundation and structure. Normally he sought out the sound, let it tell him Thrive was alive and with him, but now it made him physically ill to hear, and he had to close his eyes to stop himself from getting sick in his helmet.