Zzzap talking to ghosts

The two soldiers exchanged quick looks. “He’s talking to himself, sir,” said King. “What do you mean?”
Hardy looked at the glowing wraith through the window. “If we stayed at our stations for a while, sir, two or three hours, I think he’d forget we were in here. And he’d start talking.”
“Talking about what?”
The soldier shrugged. “About the fact he’s stuck in the cell. Things he should’ve done. Things he could try.”
“One bit about not being able to touch anything,” added King. “It’s all on the tapes.”
“So he’s thinking out loud,” said the doctor. “Not so unusual, is it?”
“It isn’t like that, sir,” said Hardy. “His phrasing and tone are very distinct. It’s like we’re hearing half a conversation he’s having with someone else.”

Excerpt From Ex-Patriots, pg 443
Peter Clines
https://books.apple.com/us/book/ex-patriots/id585738393