Sam saw in a split second of clarity what he would have to do. He didn’t like it.

The bug rushed at Sam.

The mouth blades sliced.

Sam timed his leap, shouted a desperate curse, and dove straight into the bug’s gaping mouth.

[...]

SAM LEAPED INTO the open mouth of the creature.

Head and shoulders made it in. The bug’s throat spasmed, like wet rubber, crushing the air from his lungs.

His eyes were tightly closed, but he could not close his nostrils and nearly vomited from a wave of stench like rotten meat, seaweed, and ammonia.

He grabbed with his hands, trying to get something to grip, had to pull his legs in before the mouthparts sliced, had to right now, right now, quick!

Something sharp against his calves. But the bug was just reacting, choking, not yet trying to chop him apart.

He yanked his legs in. All the way inside the wet, stinking, pulsating throat.

Not fast enough: the mouthparts clipped his right heel. He didn’t notice the pain, too awful, stifling, squashed, skin burning, blackness, no air.

He pushed his hands out and fired.

He couldn’t see the light, his eyes were shut tight. But he could feel the shudder that passed through the bug’s body.

He fired and moved his hands against the slimy insides, firing and firing, feeling his skin burn from whatever ammonia chemical was inside the creature, but then, far worse from the heat of his own killing light.

He had to stop or else he would cook himself.

He could feel the bug moving, like being in a car with square wheels, a violent shaking. The bug raced in mad panic as its insides bled and burned.

But no good, not enough, and in seconds he would die from lack of oxygen.

Ignore the pain: fire!

He laced his fingers together blindly, turning the twin beams into one. He pushed against the seizing guts of the creature and inscribed what felt like a circle.

Then silently screaming from the heat, the starvation of his lungs, the violent spasms of his own body rebelling, he kicked and kicked, pulled himself into a tight ball and kicked where he had burned, with all his fading strength.

Air!

Plague, Chapter 36 and 37