It would be interesting if Spider's senses became enhanced due to the rapid changes in his body, and he overheard Jake discussing killing him with Neytiri.
Whatever it was that Kiri did to him, the ever-growing changes in his human body sharpened everything from sound, scent, and instinct, until he could see and smell and hear just like a Na'vi can. These changes are what saved his life when he heard things he shouldn’t have. Voices hushed. Words spoken with clear intent. Plans are being made behind his back.
Jake is talking about killing him.
Spider is standing, frozen next to Sa'ata, his breathing stilled. His heart begins to pound, hard enough that he’s sure they’ll hear it, and he quickly calms himself, breathing slowly. Spider has learned, over years of half-spoken threats and careful cruelty, how to read adults when they think a child isn’t listening, when they assume a child will not understand.
Contrary to what everyone thinks of him, Spider is not stupid.
To be stupid is to get yourself killed.
He’s been surrounded by people who have hurt him, used him, or wished him gone for as long as he can remember. He’s survived because he learned to listen, to watch, to anticipate the moment a threat becomes very, very real. And now the voice he trusted more than any other, the man he idolized, the man he wanted to be like, wants him killed.
Whenever Jake and Neytiri talk about him, it’s always the same: hushed tones, clenched jaws, barely restrained emotions. Spider knows the expressions on their faces whenever they discuss what to do with him.
He knows what this is about. He knows.
Spider's stomach drops out from under him when Jake's hushed voice reaches his ears, and realization settles in, cold and absolute. Panic claws its way up his throat, but Spider forces it down. He can’t run...not yet. Not now. Fear and panic will get him killed faster than anything else. Jake is a trained soldier, and Neytiri is a highly skilled hunter and warrior. If he ran now, they would overpower him like two thanators overpowering a lone baby yerik. So, Spider does what he’s always done.
He turns around to face them, his mind whirling, and calls out like nothing is wrong. His voice sounds normal. Casual. He asks if he can go use the bathroom behind a tree across the creek.
Jake refuses. Lies. Says he has something important to discuss.
Spider presses. Just a little more. "C'mon, Jake. I really have to go."
“Then hurry up, goddamn it! We don’t have all day!”
The words hit harder than any glare from Neytiri. Jake has never yelled at him before. Ever. Spider nearly flinches, but doesn’t. He won’t give himself away. Neytiri won’t even look at him. Her face is turned away, jaw tight, eyes distant, like she's struggling with some inner turmoil. Guilt flickers there, tangled with something mournful. She understands what Jake is choosing to do, and it was confirmation to Spider that Jake was dead-set on following through with this plot. Spider gives his signature goofy grin, salutes, bright and exaggerated, a mockery of the boy they think he still is. Jake's perfect little lamb. Inside, something in his heart shatters. He moves carefully, painfully aware of every step, every breath. Too fast and they’ll suspect. Too slow, and they’ll stop him.
Behind the tree, Spider squats, hands shaking, tears streaming down his cheeks, forcing himself to act normal. The moment he’s done...
He runs like a maddened animal. Wild. Like the rabbits in Norm's old books about Earth. Branches tear at his skin. His feet sink in the mud. His lungs burn, his vision blurs with tears, he's shaking all over. Spider smears mud over himself with frantic hands, coating his skin, choking down sobs as he lowers himself and scrambles away, hiding from the sunlight. Jake and Neytiri are exceptional hunters, and Spider has learned all he needed to learn from Jake on how to hide and camouflage yourself with mud and leaves. Spider is a natural at this.
By the time Jake and Neytiri realize he’s been gone too long, Spider has already vanished. They call his name, once, then again, panic sharpening their voices, but it’s too late. Spider is silent. Hiding his tracks. He vanishes like a ghost in the trees. Jake and Neytiri return to High Camp...alone.