One of the biggest problems Foster has with communication, besides everything, is honestly the vague, intuitive fashion by which other people navigate the process. He struggles enough to articulate things within himself; his thoughts are disorganised, language elusive. Ideas and concepts shift and warp.

Psi may not have meant to, but by antagonising him so specifically, he's actually helped Foster narrow down what he's trying to say, error by error.

"It's my brain. It's in my brain, the disease is in my brain!"

Everything you are is inside your brain; your thoughts, your feelings, the very concept of the self is in the brain. Everything you do begins first inside the brain; everything you've done or not done is stored inside a few pounds of fat and blood.

His brain is diseased; he's diseased. His brain is diseased; he is a disease. It's rotting, he's rotting, rotted--

Anger is fine, anger is good! He can take anger! He wants Psi to raise his voice louder, to escalate this, to grab him by the throat and slam him to the stone floor, where he can only choke out broken syllables past the saliva and claws.

Then he could say what he really thinks, he could think and speak clearly at last--!